Very efficient computer codes to perform many-body perturbation theory (MBPT) and coupled cluster method (CCM) calculations have been written and employed for the first time in large-scale ab initio calculations of potential energy surfaces.

Very efficient computer codes to perform many-body perturbation theory (MBPT) and coupled cluster method (CCM) calculations have been written and employed for the first time in large-scale ab initio calculations of potential energy surfaces. (Author)

A detailed breakdown of many-body perturbation theory contributions through third order is presented for the ground-state removal energies of cesium and thallium, with the aim of identifying which Goldstone diagrams are numerically dominant. A comparison of these diagrams with Feynman graphs is made. A discussion of the issues involved in carrying out ab ...

The framework of ab initio density-functional theory (DFT) has been introduced as a way to provide a seamless connection between the Kohn-Sham (KS) formulation of DFT and wave-function based ab initio approaches [R. J. Bartlett, I. Grabowski, S. Hirata, and S. Ivanov, J. Chem. Phys. 122, 034104 (2005)]. Recently, ...

The ab initio determination of the electronic structure of molecules is a many-fermion problem involving the approximate description of the motion of the electrons in the field of fixed nuclei. It is an area of research which demands considerable computat...

The electronic spectrum of a chemically contacted molecule in the junction of a scanning tunneling microscope can be modified by tip retraction. We analyze this effect by a combination of density-functional, many-body perturbation, and numerical renormalization-group theories taking into account both the nonlocality and the dynamics of electronic ...

We present an ab initio study of the lowest states of five temporary anions: C6H6(-), C6H5F(-), 1,4-C6H4F2(-), 1,2,3-C6H3F3(-), and 1,3,5-C6H3F3(-). Vertical positions and widths of anionic resonances have been calculated within the stabilization graph approach using the multipartitioning form of the many-body perturbation theory for ...

Ab initio techniques are used to calculate the effective work function (Weff) of a TiN/HfO2/SiO2/Si stack representing a metal-oxide-semiconductor (MOS) transistor gate taking into account first order many body effects. The required band offsets were calculated at each interface varying its composition. Finally, ...

In this paper we report a theoretical study of the static dipole polarizability of two one-dimensional structures: (a) linear carbon chains Cn (n=2-10) and (b) ladderlike planar boron chains Bn (n=4-14). The polarizabilities of these chains are calculated both at the Hartree-Fock and the correlated levels by applying accurate ab initio quantum-chemical ...

Hamiltonian light-front quantum field theory constitutes a framework for the non-perturbative solution of invariant masses and correlated parton amplitudes of self-bound systems. By choosing light-front gauge and adopting a basis function representation, we obtain a large, sparse, Hamiltonian-matrix for mass eigenstates of gauge theories that is solvable by adapting the ...

Ab initio quantum chemistry methods based upon many-body perturbation theory (MBPT) and coupled-cluster (CC) theory have been developed and applied to potential energy surfaces for transient molecules. Studies included decomposition pathways for formaldehyde, methanol, the formyl radical and the inorganic radical ...

Van der Waals interaction potentials of the square planar D{sub 4h} and regular tetrahedral T{sub d} configurations of He{sub 4} were examined at the matrix Hartree-Fock, many-body perturbation theory, coupled-cluster theory, and configuration interaction levels of ab initio theory. Potential energy minima, ...

We apply the so-called diabatization method by Baer (1975 Chem. Phys. Lett. 35 112) to describe photo-excited electronic states. The diabatization is a unitary transformation which, applied to the adiabatic eigenstates of the quantum Hamiltonian, allows for treating the non-adiabatic effects correctly. These effects are all those which appear in the Born-Oppenheimer approximation as the areas of ...

Ground state properties of crystalline ice Ih are investigated by combining periodic Hartree-Fock calculations with a many-body expansion for the electron correlation energy using second-order many-body perturbation theory and coupled-cluster techniques. Very good agreement with experimental data can already be achieved by considering two-body correlation ...

We report the first-principles computation of rate constants for atmospheric reactions, by combining variational transition state theory (VTST) and high-level electronic structure theory. Extending the direct dynamics approach, the rate constants for OH+HCl were computed, directly, using {ital ab initio} electronic structure theory at the second-order ...

An efficient model describing the He-atom scattering process is presented. The He-surface interaction potential is calculated from first principles by exploiting second-order Rayleigh-Schr�dinger many-body perturbation theory and fitted by using a variety of pairwise interaction potentials. The attractive part of the fitted analytical form has been ...

This work is devoted to the elucidation of the applicability of the jellium model to the description of alkali cluster properties. We compare the jellium model results with those derived within ab initio theoretical approaches and with experiments. On the basis of Hartree-Fock and local-density approximations we have calculated the binding energies per ...

During the past decade, computer simulations based on a quantum-mechanical description of the interactions between electrons and between electrons and atomic nuclei have developed an increasingly important impact on solid-state physics and chemistry and on materials science-promoting not only a deeper understanding, but also the possibility to contribute significantly to materials design for ...

-body mul- tipartitioning perturbation theory MPPT ,9 which seems to be more adequate for the description. Ab initio finite-field MPPT transition dipole moment functions obtained with the two atomic basis ( em PSZ ) and KN--Ref. 7 ( em KN ); b ab initio calculated in the present work FF-MPPT, ...

the possible existence of high mass neutron star observations favors a stiff EoS. Ab initio calculations initio calculations of the nuclear many�body problem predict a density and isospin behavior of the Eo. The predictive power of such density functionals at supra�normal densities is restricted. Ab ...

Partial contents include: time-dependent theory of photoabsorption processes; molecular simulation of a chemical reaction in supercritical water; many-body methods for electron correlation; conformational studies of PAF and PAF-antagonists; electric properties of atomic anions; theoretical interpretation of the Li4(-) spectrum using path integrals and ab ...

The hyperfine structure of the long-lived 5D3/2 and 5D5/2 levels of Ba+ ion is analyzed. A procedure for extracting relatively unexplored nuclear magnetic moments ? is presented. The relevant electronic matrix elements are computed in the framework of the ab initio relativistic many-body perturbation theory. ...

Starting from the Argonne V18 nucleon-nucleon interaction and using the Unitary Correlation Operator Method, a correlated interaction vUCOM has been constructed, which is suitable for calculations within restricted Hilbert spaces. In this work we employ the vUCOM in Hartree-Fock, perturbation-theory and RPA calculations and we study the ground-state properties of various ...

The following final report summarizes four years of research for ONR on the topic of 'Many-Body Quantum Mechanical Studies of Molecular Clusters.' There are two primary aspects of this effort, a methodological part focusing on new first principle (i.e. ab initio) multi-reference coupled-cluster methods for obtaining improved solutions to the Schroedinger ...

The optimized structure and electronic properties of neutral and singly charged magnesium clusters have been investigated using ab initio theoretical methods based on density-functional theory and systematic post-Hartree-Fock many-body perturbation theory accounting for all electrons in the system. We have ...

Energies, transition rates, and electron electric-dipole-moment (EDM) enhancement factors are calculated for low-lying states of Ce IV and Pr V using relativistic many-body perturbation theory. This study is related to recent investigations of the more complicated Gd IV ion, which is promising for electron EDM experiments. The ions Ce IV and Pr V both have ...

We perform ab initio calculations of isotope shifts for isotopes of cesium (from A=123 to A=137) and francium (from A=207 to A=228). These calculations start from the relativistic Hartree-Fock method and make use of several techniques to include correlations. The field (volume) isotope shift is calculated by means of an all-order correlation potential ...

We perform ab initio calculations of isotope shifts for isotopes of cesium (from A=123 to A=137 ) and francium (from A=207 to A=228 ). These calculations start from the relativistic Hartree-Fock method and make use of several techniques to include correlations. The field (volume) isotope shift is calculated by means of an all-order correlation ...

A new approach for surface studies using the density functional formalism for structural determination and a first principles many-body theory for the quasiparticle surface state energies is discussed. The many-body calculation involves the evaluation of ...

Research progress on an alternative method to ab initio variational and perturbative approaches for the electronic structure of molecules is described. Progress in the report year on the evaluation of (1) molecular properties, (2) energy derivatives with ...

... and many-body perturbation theory (MBPT) methods for the accurate inclusion of electron correlation in ab initio quantum chemical calculations of ...

The CCSD(T) method, singles and doubles coupled-cluster theory plus a perturbational estimate of the

Tautomerization and phototautomerization of [2,2[prime]-bipyridine]-3,3[prime]-diol is investigated by means of infrared, Raman, and time-resolved resonance Raman spectroscopies and ab initio theoretical calculations. Full ab initio SCF (self-consistent field method) geometry optimization followed by MBPT ...

We develop a new ab initio many-body approach capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters. This approach preserves translational symmetry and ...

For many problems in nuclear, high-energy and solid-state physics a crucial step toward a solution involves a diagonalization or simplification of the Hamiltonian of a many-body quantum-mechanical system. Problems of interest include renormalization of the Hamiltonian to accommodate excluded basis spaces, decoupling of a model space region of special interest from irrelevant configurations, or ...

such as H2 (see ref. 11 and references therein), to the best of our knowledge, the only quantum-chemical ab as an Advance Article on the web 16th April 2009 DOI: 10.1039/b822262b By means of non-perturbative ab initio antiaromatic rings with less than one hundred carbon atoms. I. Introduction The full ab ...

We discuss an efficient approach to excited electronic states within ab initio many-body perturbation theory (MBPT). Quasiparticle corrections to density-functional theory result from the difference between metallic and nonmetallic dielectric screening. They are evaluated as a small ...

A systematic method for approximating the ab initio electronic energy of crystal lattices has been improved by the incorporation of long range electrostatic and dispersion interactions. The effect of these long range interactions on the optimization of the crystal structure is reported. The harmonic lattice dynamics have been evaluated to give phonon ...

A systematic method for approximating the ab initio electronic energy of crystal lattices has been improved by the incorporation of long range electrostatic and dispersion interactions. The effect of these long range interactions on the optimization of the crystal structure is reported. The harmonic lattice dynamics have been evaluated to give phonon ...

The importance of many-body interactions is investigated for m=4,6,8 in Cu(sup 2+)(H(sub 2)O)m clusters using ab initio molecular orbital theory. A slow convergence of the interaction terms to the full many-body result is found similar to what was found i...

Empirical many-body potentials of the glue-type have been constructed for the Al-Pb system using the force matching method. The potentials are fitted to experimental data, physical quantities derived from ab initio linear muffin-tin orbitals calculations and a massive quantum mechanical database of atomic forces generated using ...

Vibrational frequency shift upon the 1 : 1 acetone-iodine complex formation was determined from geometries optimized at the SCF (Self Consistent Field) and MP2 (Moeller-Plesset Second Order Perturbation) levels using the ab initio MO (Molecular Orbital) t...

Ab initio calculations using the Molier-plesser perturbation theory were carried out on the H-atom abstraction reaction from dibromomethane by hydroxyl radical attack. Geometry optimization and vibrational frequency calculations at the MP2 level were perf...

Ab initio calculations using the Molier-plesser perturbation theory were carried out on the H-atom abstraction reaction from dibromomethane by hydroxyl radical attack. Geometry optimization and vibrational frequency calculations at the MP2 level were performed on all reactants, p...

A unified summary is presented of the mathematical approach developed by McDowell for employing perturbation theory to correct for basis-set incompleteness in ab initio SCF calculations. Revised expressions for the corrections to the wavefunction both in ...

Atomic polarization phenomena impinge upon a number of areas and processes in physics. The dielectric constant and refractive index of any gas are examples of macroscopic properties that are largely determined by the dipole polarizability. When it comes to microscopic phenomena, the existence of alkaline-earth anions and the recently discovered ability of positrons to bind to many atoms are ...

We present ab initio calculations of the phonon self energy of transition metals obtained using second order many body perturbation theory. ootnotetextS. Narasimhan and D. Vanderbilt, Phys. Rev. B, 43, 4541 (1991) The code we have implemented ootnotetextL. Chaput, A. Togo, I. Tanaka and G. Hug, ...

A complete intermolecular potential energy surface (PES) of the H2O-CO2 complex has been constructed using a large scale ab initio calculations. This PES was sampled at 23 000 points of a five dimensional configuration space of the intermolecular coordinates. The interaction energy was calculated using the second order M�ller-Plesset ...

Hamiltonian light-front quantum field theory constitutes a framework for the non-perturbative solution of invariant masses and correlated parton amplitudes of self-bound systems. By choosing the light-front gauge and adopting a basis function representation, we obtain a large, sparse, Hamiltonian matrix for mass eigenstates of gauge theories that is solvable by adapting the ...

We present absorption spectra of group IB and IIB atoms and dimers, obtained with two state-of-the-art computational methods using ab initio pseudopotentials: the many body perturbation technique GWBSE and the time-dependent density functional theory with the local density approximation ...

The van der Waals coefficients C{sub 6}, C{sub 8}, and C{sub 10} for H and He interactions with the alkali-metal (Li, Na, K, and Rb) and alkaline-earth-metal (Be, Mg, Ca, and Sr) atoms are determined from oscillator strength sum rules. The oscillator strengths were computed using a combination of ab initio and semiempirical methods. The dispersion ...

The study of the minimum Born-Oppenheimer structures of the protonated water clusters, (H2O)nH+, is performed for n=20 and 21. The structures belonging to four basic morphologies are optimized at the Hartree-Fock, second-order many-body perturbation theory and coupled cluster level, with the 6-31G, 6-31G*, and 6-311G** basis sets, using the parallel ACES ...

et al. The electronic properties of magnets and exchange-enhanced paramagnets are strongly influenced by the spin-flip fluctuations. In particular, their important role in the pnictide high-temperature superconductivity is has been conjectured [Mazin & Johannes, Nat. Phys. 5, 141 (2009)]. To formulate a parameter free model of electron-electron interaction involving emission and absorption of ...

We propose an importance truncation scheme for the no-core shell model, which enables converged calculations for nuclei well beyond the p-shell. It is based on an a priori measure for the importance of individual basis states constructed by means of many-body perturbation theory. Only the physically relevant states of the no-core model space are considered, which leads to a ...

We present an analysis of the dielectric properties of the three polymorphs of TiO? (rutile, anatase and brookite phases), using ab initio time-dependent density functional perturbation theory based on the Vignale-Kohn functional. We implement this functional, which incorporates many-body effects, using the ...

We present an analysis of the dielectric properties of the three polymorphs of TiO2 (rutile, anatase and brookite phases), using ab initio time-dependent density functional perturbation theory based on the Vignale�Kohn functional. We implement this functional, which incorporates many-body effects, using the ...

Methyl hydrogen peroxide (MHP), one of the simplest organic hydroperoxides, is a strong oxidant, with enhanced activity in aqueous ambience. The present study investigates, at the molecular level, the role of hydrogen bonding that is conducive to cluster formation of MHP with water molecules from its peroxide end, with the methyl group remaining hydrophobic for up to five water molecules. ...

We present ab initio electronic structure calculations for small, spherical jellium clusters or quantum dots (QD) in the GW self-energy approach. In particular we analyse the effects of exchange and correlation, which give rise to image effects in these structures. In recent years, GW (G: Greens Function, W: Screened Coulomb Potential) has successfully ...

The comprehensive study of the ab initio pair potentials and prediction of properties for acetonitrile and methanol [J. Chem. Phys. 116, 7627 (2002), preceding paper] is extended to examine the vapor-liquid equilibria of their mixture. An ab initio pair interaction potential is developed for the ...

Perturbative variational calculations of thermodynamic and structural properties of liquid metals, based on the use of ab initio and highly reliable nonlocal pseudopotentials for the electron-ion interactions and of the fluid of charged hard spheres as re...

Under AFOSR support over several years, coupled-cluster (CC) and many-body perturbation theory (MBPT) methods for the accurate inclusion of electron correlation in ab initio quantum chemical calculations of molecules have been definitively established as ...

Ab initio calculations of the electronic structure of Hn- and Hn+ clusters have been carried out using accurate Gaussian basis sets and with levels of theory up to fourth-order perturbation theory (MP4) and single and double excitation configuration inter...

ACES II, a new program system for ab initio electronic structure calculations is described. The strengths of ACES II involve the use of many-body perturbation theory (MBPT) and coupled-cluster (CC) theory for calculating the energy, geometry, spectra, and...

We develop a new ab initio many-body approach capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters. This approach preserves translational symmetry and ...

We develop a new ab initio many-body approach capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters. This approach preserves translational symmetry and ...

We develop a new ab initio many-body approach capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters. This approach preserves translational symmetry and ...

We develop a new ab initio many-body approach capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters. This approach preserves translational symmetry and ...

We develop a new ab initio many-body approach capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters. This approach preserves translational symmetry and ...

The ab initio/classical free energy perturbation (ABC-FEP) method proposed previously by Wood et al. [J. Chem. Phys. 110, 1329 (1999)] uses classical simulations to calculate solvation free energies within an empirical potential model, then applies free energy perturbation theory to determine the effect of changing ...

Our program concerns the theoretical investigations of the dynamic effects of relativity and electron correlations on atomic processes, and the developments of relativistic many-body techniques for atomic structure calculations. Currently, we are studying atomic hyperfine structures (hfs) with the multiconfiguration Dirac-Fock (MCDF) technique. This is a very general ...

This program is directed towards the development of new theoretical formalisms and practical computational methods for ab initio investigation of the structure and quantum dynamics of atoms and molecules in intense laser fields. This report contains some of the major accomplishments over the past year like the investigation of collisional processes in the ...

This program is directed towards the development of new theoretical formalisms and practical computational methods for ab initio investigation of the structure and quantum dynamics of atoms and molecules in intense fields. Major accomplishments over the past year are summarized.

, larry diamond. (credit: rod searcey) right: Jean oi, william haas professor in chinese politics, professor of chinese economy, ucsd (center), lyric hughes hale, founder of china online (right of center), and david hale, founder of david hale global economics (far right), address the leading question, "can china

In this work we present a theoretical and experimental study of the acetylene-hydrogen system. An ab initio potential surface has been obtained by ab initio quantum chemistry methods. This 4-dimensional potential is further used to compute pressure broadening coefficients of C2H2 isotropic Raman Q lines on a large ...

The ability of simple levels of ab initio molecular orbital theory to describe with reasonable accuracy the energetics of isotopic exchange processes is demonstrated. Three levels of ab initio molecular orbital theory have been surveyed. The first two levels are single-determinant Hartree-Foch methods utilizing the ...

The structural, electronic and dynamic properties of cesium chloride, ZrRu and ZrZn were studied by employing an ab initio pseudopotential method and a linear response scheme, within the generalized gradient approximation. The calculated lattice constant, bulk modulus and first-order pressure derivative of the bulk modulus were reported in B2 structure and ...

The importance of many-body interactions is investigated for m=4,6,8 in Cu{sup 2+}(H{sub 2}O)m clusters using ab initio molecular orbital theory. A slow convergence of the interaction terms to the full many-body result is found similar to what was found in a previous study of Fe{sup 3+}(H{sub 2}O)m clusters. Implications for molecular ...

The importance of many-body interactions is investigated for m=4,6,8 in Cu[sup 2+](H[sub 2]O)m clusters using ab initio molecular orbital theory. A slow convergence of the interaction terms to the full many-body result is found similar to what was found in a previous study of Fe[sup 3+](H[sub 2]O)m clusters. Implications for molecular ...

Atomistic simulations of alloys at the classic--or empirical--level face the challenge to correctly model basic thermodynamic properties. In this work we propose a methodology to generalize many-body classic potentials to incorporate complex formation energy curves. Application to Fe-Cr allows us to correctly predict the order vs segregation tendency in this alloy, as observed ...

The difficulty in accurate determination of the nuclear quadrupole moment of the first I=3/2 excited nuclear state of 57Fe from electronic structure calculations of the iron electric field gradient combined with M�ssbauer measurements of the nuclear quadrupole splitting in the isomer shift is addressed by comparing ab initio with density functional ...

Zinc oxide is a key material for optoelectronic applications, whose transport properties are typically dominated by the lattice vibrations. We report here the phonon-dispersion relations of wurtzite ZnO at 10 K, as determined by using inelastic neutron scattering. The experimental data are analyzed with the aid of ab initio calculations based on ...

The structures and energies of the molten salt vapor complexes LiAlF(sub 4) and NaAlF(sub 4) are studied using new high level ab initio molecular orbital methods. The structures are determined using Moller-Plesset perturbation theory to second-order and t...

High-level quantum-chemical ab initio coupled-cluster and multiconfigurational perturbation methods have been used to compute the vertical and adiabatic electron affinities of the five canonical DNA and RNA nucleobases: uracil, thymine, cytosine, adenine, and guanine. The present results aim for the accurate determination of the ...

Hydrogen bonding in infinite (HF)_infinity and (HCl)_infinity bent (zig-zag) chains is studied using the ab initio coupled-cluster singles and doubles (CCSD) correlation method. The correlation contribution to the binding energy is decomposed in terms of non-additive many-body interactions between the monomers in the chains, the ...

We used a variational approach adapted to a quantum molecular-dynamics code to determine the best reference potential for warm dense aluminum. This ab initio variational approach was based on the Gibbs-Bogolyubov inequality. We used many-body reference systems interacting through inverse-power-law potentials, among which the Coulomb ...

Recent advances in ab initio quantum many-body methods and growth in computer power now enable highly precise calculations of nuclear structure. The precision has attained a level sufficient to make clear statements on the nature of 3-body forces in nuclear physics. Total binding energies, spin-dependent structure effects, and ...

We extend the ab initio no-core shell model/resonating-group method (NCSM/RGM) to projectile-target binary-cluster states where the projectile is a deuteron. We discuss the formalism in detail and give algebraic expressions for the integration kernels. Using a soft similarity-renormalization-group evolved chiral nucleon-nucleon potential, we calculate ...

We present an overview of recent results and developments of the no-core shell model (NCSM), an ab initio approach to the nuclear many-body problem for light nuclei. In this aproach, we start from realistic two-nucleon or two- plus three-nucleon interactions. Many-body calculations are performed using a finite ...

We report full-dimensional, ab initio potential energy (PES) and dipole moment surfaces (DMS) for water. The PES is a sum of one-, two- and three-body terms. The three-body potential is a fit, reported here, to roughly 30,000 intrinsic three-body energies obtained with second-order M�ller-Plesset perturbation theory (MP2) and using ...

The development of modern materials science has led to a growing need to understand the phenomena determining the properties of materials on an atomistic level. As the behavior of atoms and electrons is governed by the laws of quantum mechanics, accurate and efficient techniques for solving the basic quantum-mechanical equations for very complex many-atom, many-electron systems are required. The ...

The development of modern materials science has led to a growing need to understand the phenomena determining the properties of materials on an atomistic level. As the behavior of atoms and electrons is governed by the laws of quantum mechanics, accurate and efficient techniques for solving the basic quantum-mechanical equations for very complex many-atom, many-electron systems are required. The ...

The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. Above all nuclear scattering and reactions, which require the solution of the many-body quantum-mechanical problem in the continuum, represent an extraordinary theoretical as well as computational challenge for ab ...

We present in detail the formulation of the ab initio theory we have developed for the calculation of the macroscopic second-order susceptibility ?(2) . We find a general expression for ?(2) valid for any fields, containing the ab initio relation between the microscopic and macroscopic formulation of the ...

The hydration free energy, structure, and dynamics of the zinc divalent cation are studied using a polarizable force field in molecular dynamics simulations. Parameters for the Zn(2+) are derived from gas-phase ab initio calculation of Zn(2+)-water dimer. The Thole-based dipole polarization is adjusted based on the Constrained Space Orbital Variations ...

The hydration free energy, structure, and dynamics of the zinc divalent cation are studied using a polarizable force field in molecular dynamics simulations. Parameters for the Zn²⁺ are derived from gas-phase ab initio calculation of Zn²⁺-water dimer. The Thole-based dipole polarization is adjusted based on the ...

A systematic ab initio comparative study of the (hyper)polarizabilities of selected III-V stoichiometric semiconductor clusters has been carried out. Our investigation focuses on the ground state structures of the dimers and on two dissimilar trimer configurations of aluminum, gallium, indium phosphide and arsenide. The basis set effect on both the ...

Ultracold atomic gases in optical lattices have proven to be a controllable, tunable and clean implementation of strongly interacting quantum many-body systems. An essential prospect for such quantum simulators is their ability to map out the phase diagram of fundamental many-body model Hamiltonians. However, the results need to be validated first for ...

An embedded atom type many-body model for describing rare-gas solids is developed. Model parameters are obtained by fitting zero-temperature compression curves, bulk moduli, and C44 elastic constants to experimental and ab initio data. The model is then used to calculate the pressure-dependent elastic constants, Cauchy discrepancies, ...

We introduce a scheme to include many-body screening processes explicitly into a set of self-consistent equations for electronic-structure calculations using the Gutzwiller approximation. The method is illustrated by the application to a tight-binding model describing the strongly correlated ?-Ce system. With the inclusion of the 5d electrons into the local Gutzwiller ...

We introduce a scheme to include many-body screening process explicitly into self-consistent equations for electronic structure calculations by employing Gutzwiller approximation. The method is illustrated by applying to a tight-binding model of the strongly correlated ?-Ce. The critical Coulomb repulsion Uff^c between the 4f electrons for electronic phase transition can be ...

A new global potential energy surface is reported for the (4)A'' ground electronic state of the N(3) system from double many-body expansion theory and an extensive set of accurate ab initio energies extrapolated to the complete basis set limit. It shows three equivalent metastable potential wells for C(2v) geometries that are separated ...

Many-body multipartitioning perturbation theory (MPPT) was applied to calculate the potential energy of 11 lowest electronic states of the NaRb molecule, A,C 1?+-X 1?+, B,D 1?-X1?+, D 1?-A 1?+ and D 1?-B 1? transition dipole moments, as well as nonadiabatic L-uncoupling matrix elements between the examined 1? and four lowest 1?+ states for both 23Na85Rb ...

... This study involves: Ab-initio crystal orbitals and polymer orbitals; Ab-initio coupled cluster program; Ab-initio quantum chemical calculations and ...

by means of the many-body multipartitioning perturbation theory (MPPT). The ab initio d(R) estimates [22] by means of the many-body multipartitioning perturbation theory (MPPT) [24, 25]. In order. The procedure of MPPT correlation treatment employed in the present work was generally similar to that used

-body multipartitioning perturbation theory MPPT was applied to calculate the potential energy of 11 lowest electronic for both 23 Na85 Rb and 23 Na87 Rb isotopomers. The relevant MPPT ab initio matrix elements and energy initio calcula- tions performed in 9 by the multipartitioning perturbation theory MPPT ...

Ab initio calculations demonstrate that specific zwitterionic molecules which have a {sigma}-bonded donor-acceptor system show an enhanced hyperpolarizability ({beta}) value when the effects of electron correlations are considered. Ab initio second-order Moeller-Plesset perturbation theory ...

Applying time differential perturbed angular correlation (TDPAC) spectroscopy and ab initio calculations, we have investigated possible lattice instabilities in Sr(2)RuO(4) by studying the electric quadrupole interaction of a (111)Cd probe at the Ru site. We find evidence for a dynamic lattice distortion, revealed from the observations ...

Ab initio density functional theory (DFT) and density function perturbation theory (DFPT) have been used to investigate the thermal properties of the fcc Al3Mg and Al3Sc alloys over a wide range of pressure and temperature, in comparison with fcc Al. Phonon dispersions were obtained at equilibrium and strained configurations by density ...

Electronic many-body effects alone can be responsible for the migration of a positive charge created upon ionization in molecular systems. Here, we report an ultrafast charge migration taking place after valence ionization of the molecule 4-methylphenol. The results obtained by a fully ab initio methodology show that the positive ...

The U-Al binary system exhibits the formation of three intermetallic compounds: cubic Laves phase C15 UAl2, cubic L12 UAl3, and orthorhombic D1b UAl4. However, some uncertainties are found in the literature concerning UAl4 structure and composition. A computational first principles based approach is a useful tool to shed some light on this problem. To the author's knowledge there are no such ...

The relation between superfluidity and Bose condensation in {sup 4}He provides lessons that may be valuable in understanding the strongly correlated electron system of high {Tc} superconductivity. Direct observation of a Bose condensate in the superfluid by deep inelastic neutron scattering measurements has been attempted over many years. But the impulse approximation, which relates momentum ...

A rigorous theory for the determination of the van der Waals interactions in colloidal systems is presented. The method is based on fluctuational electrodynamics and a multiple-scattering method which provides the electromagnetic Green's tensor. In particular, expressions for the Green's tensor are presented for arbitrary, finite collections of colloidal particles, for infinitely ...

An ab initio theoretical study shows that a previously neglected intra-atomic many-body effect has important consequences for the X-ray photoelectron spectra (XPS) of transition metal atoms and cations. For the Mn 3s XPS, inclusion of this effect correctly yields the multiplet splitting, properly describes the absolute binding energy, ...

Infrared spectra of solutions of trifluoroethene and dimethyl ether, acetone, or oxirane in liquid krypton and liquid argon have been studied. For each Lewis base the formation of a 1:1 complex with the Lewis acid was observed. The C-H stretching of trifluoroethene being perturbed by a strong Fermi resonance, the complexes with trifuloroethene-d were also investigated and ...

Intermolecular interaction potentials of the trifluoromethane dimer in 15 orientations have been calculated using the Hartree-Fock (HF) self-consistent theory and the second-order M�ller-Plesset (MP2) perturbation theory. Single point energies at important geometries were also calibrated by the coupled cluster with single and double and perturbative ...

We employ recent flexible ab initio potential energy and dipole surfaces [Y. Wang, X. Huang, B. C. Shepler, B. J. Braams, and J. M. Bowman, J. Chem. Phys. 134, 094509 (2011)] to the calculation of IR spectra of the intramolecular modes of water clusters. We use a quantum approach that begins with a partitioned normal-mode analysis of ...

This is the final report for a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Ab initio quantum chemistry has proven to be a valuable tool for understanding the electronic structure of small molecules containing 5--50 atoms. Calculations on larger systems have been prohibitive because ...

Molecular electrostatic potential (MESP) guidelines are employed for understanding the reactivity and hydration patterns in alkanediol molecules. The deeper oxygen lone pair MESP minima indicate stronger basicity of 1,n-diols and 2,4-pentanediol (2,4-PeD) as compared to that of vicinal diols. The existence and strength of the intramolecular hydrogen bond in diols are gauged in terms of the ...

We study time dependent correlation functions of ideal classical and quantum gases using methods of equilibrium statistical mechanics. The basis for this is the path integral formalism of quantum mechanical systems. By this approach the statistical mechanics of a quantum mechanical system becomes the equivalent of a classical polymer problem in four dimensions where imaginary time is the fourth ...

... from federally funded research, testing and training ... for Research Development Test and Evaluation ... COMPENDIUM OF AB INITIO CALCULATIONS ...

... Accession Number : ADA219907. Title : An Ab Initio Study of the Geometry and Rotational Barrier of 4- Phenylimidazole. ...

... from federally funded research, testing and training ... and agencies for Research Development Test and Evaluation ... Title : Ab Initio Calculations of the ...

... Title : Ab Initio Calculation of Vibrational Absorption and Circular Dichroism Spectra Using Density Functional Force Fields. ...

... Title : AB Initio Quantum Chemical Investigations of Solubilities in Supercritical Solutions. Descriptive Note : Conference Paper,. ...

In recent years, the Similarity Renormalization Group has provided a powerful and versatile means to soften interactions for ab initio nuclear calculations. The substantial contribution of both induced and initial three-body forces to the nuclear interaction has required the consistent evolution of free-space Hamiltonians in the three-particle space. We ...

We report on a global potential energy hypersurface for the upper sheet of the lowest triplet state of H3+. The analytic representation is based on the double many-body expansion theory. The ab initio data points, calculated with a large cc-pV5Z basis, are represented with a root mean square deviation of only 5.54 cm(-1) in the energy ...

This work regards the passage of fast electrons through matter, and in particular how electrons scatter and lose energy within a solid. The basic quantum theory of these scattering processes was first considered in the early- to mid-20th century by Bohr, Bethe, Fermi, and others. This work extends our understanding of how a relativistic electron scatters off, and loses energy to, a complex ...

Highly accurate analytical intermolecular potential energy surfaces (PESs) of the complexes composed of the water molecule and the rare gas (Rg) atom are presented for Rg=He, Ne, Ar, and Kr. These PESs were scanned using the supermolecule coupled cluster singles and doubles including connected triples method [CCSD(T)]. Efficient basis sets including the bond functions (3s3p2d1f1g) enabled the ...

We build a new ab initio many-body approach [1] capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method [2] with the ab initio no-core shell model [3]. In this way, we complement a microscopic-cluster technique with the use ...

The ?4 fundamental vibration spectrum of the weakly bound complex Ar-CH4 in the 7?m region was discovered, analyzed, and compared with a synthesized spectrum, derived from ab initio calculations. The measurements were made by probing a supersonic gas expansion with a tunable diode laser (TDL) spectrometer. Several bands of Ar-CH4 associated with different ...

The S/sub N/2 reaction between ammonia and formic acid has been studied as a model reaction for peptide bond formation using the semiempirical MNDO and ab initio molecular orbital methods. Two reaction mechanisms have been examined, i.e., a stepwise and a concerted reaction. The stationary points of each reaction including intermediate and transition ...

This study address the adequacy of ab initio pair interaction energy potentials for the prediction of macroscopic properties. Recently, Bukowski et al. [J. Phys. Chem. A 103, 7322 (1999)] performed a comprehensive study of the potential energy surfaces for several pairs of molecules using symmetry-adapted perturbation theory. These ...

yambo is an ab initio code for calculating quasiparticle energies and optical properties of electronic systems within the framework of many-body perturbation theory and time-dependent density functional theory. Quasiparticle energies are calculated within the GW approximation for the self-energy. Optical properties are evaluated either ...

The behavior of various contributions to the fleft-right-arrowf transition amplitude defined up to the third order in perturbation theory is analyzed. Main attention is paid to the third-order contributions which are due to electron correlation inside the rare earth ion and arise from the static and dynamic models. The discussion is based on the numerical results of exact ...

The third-order electron-correlation theory of two-photon absorption in rare earth ions in crystals has been extended by the effective operators arising from doubly excited configurations. The approach defined in terms of one-particle effective operators has been applied to the Pr/sup +3/, Nd/sup +3/, Eu/sup +3/, Gd/sup +3/, Tb/sup +3/, and Tm/sup +3/ ions. The relative importance of third-order ...

The structures, interaction energies and vibrational spectra of the electron donor-acceptor complexes formed between boron trifluoride, as Lewis acid, and methanol and methanethiol, as Lewis bases, have been determined by means of ab initio calculations at the level of second order M�ller Plesset perturbation theory, using a ...

Long range interactions between the ground state alkali diatomics Na(2)-Na(2), K(2)-K(2), Na(2)-K(2), and NaK-NaK are examined. Interaction energies are first determined from ab initio calculations at the coupled-cluster with singles, doubles, and perturbative triples [CCSD(T)] level of theory, including counterpoise corrections. Long ...

Interaction potentials of the iodine atom, atomic cation, and anion with light rare-gas atoms from He to Ar are calculated within the unified ab initio approach using the unrestricted coupled-cluster with singles and doubles and perturbative treatment of triples correlation treatment, relativistic small-core pseudopotential, and an ...

Potassium ion in water plays a very important role in chemistry and biology. In this paper, we investigated the hydration structure and coordination of K(+) solvation in water at 300 and 450 K using ab initio Car-Parrinello molecular dynamics. The K(+)-oxygen radial distribution function indicated that the perturbation of K(+) on the ...

The linear and nonlinear optical (NLO) properties of the cis and trans isomers of diphenylbenzobisoxazole (PBO) and diphenylbenzobisthiazole (PBT) have been calculated by ab initio time-dependent coupled perturbed Hartree-Fock method using a split-valence basis set. The second-order NLO susceptibilities of the trans isomers are ...

Extensive ab initio calculations using a complete active space second-order perturbation theory wavefunction, including scalar and spin-orbit relativistic effects with a quadruple-zeta quality basis set were used to construct an analytical potential energy surface (PES) of the ground state of the [H, O, I] system. A total of 5344 ...

We outline the ab initio no core shell model and present recent results. Nuclear properties are evaluated with two-nucleon (NN) and three-nucleon interactions (TNI) derived within effective field theory (EFT) based on chiral perturbation theory (ChPT). Fitting two available parameters of the TNI generates good descriptions of light ...

We present an ab initio study of the relaxations introduced in TiO (2) when a Cd impurity substitutes a Ti atom and an experimental test of this calculation by a perturbed-angular-correlation (PAC) measurement of the orientation of the electric-field gradient (EFG) tensor at the Cd site. The ab ...

Several excited singlet electronic states of purine nucleobases and related derivatives have been calculated using high-level multireference perturbation theory methods. Purine derivatives with one or two amino or carbonyl groups substituted at positions C(2) and/or C(6) of the purine ring have been included in the study. The effect of the substituents on excited-state ...

We have performed an ab initio study of the thermodynamical properties of rare-earth�magnesium intermetallic compounds MgRE (RE=Y, Dy, Pr, Tb) with B2-type structures. The calculations were carried out in the framework of density functional theory and density functional perturbation theory in combination with the quasiharmonic ...

Geometry optimization, energy calculation, and ab initio vibrational analysis were carried out on different conformers of singlet and triplet hydroxyethynylcarbene and 3-hydroxypropadienylidene. They are probable products of the reaction C{sub 3} + H{sub 2}O. Theoretical methods used include restricted Hartree-Fock, unrestricted Hartree-Fock natural and ...

The interaction-induced contribution to the NMR shielding constants in homonuclear A2 and heteronuclear AB (A,B=He,Ne,Ar) dimers is obtained ab initio by employing a coupled cluster singles and doubles with perturbative treatment of triples wave function model and extended correlation-consistent basis sets. The second virial ...

The structures and energies of the molten salt vapor complexes LiAlF{sub 4} and NaAlF{sub 4} are studied using new high level ab initio molecular orbital methods. The structures are determined using Moller-Plesset perturbation theory to second-order and the total energies are determined using a recently introduced modification of ...

The structures and energies of the molten salt vapor complexes LiAlF[sub 4] and NaAlF[sub 4] are studied using new high level ab initio molecular orbital methods. The structures are determined using Moller-Plesset perturbation theory to second-order and the total energies are determined using a recently introduced modification of ...

This paper reports ab initio calculations of rare gas (RG=Kr, Ar, Ne, and He) dimer quadrupoles at the second order of Moeller-Plesset perturbation theory (MP2). The study reveals the crucial role of the dispersion contribution to the RG{sub 2} quadrupole in the neighborhood of the equilibrium dimer separation. The magnitude of the ...

Floquet theory is used to describe the response of a molecule to applied radiation electric field. The method of ab initio calculation of frequency dependent (hyper)polarizabilities based on combination of perturbation theory with the finite field method has been developed. Electron correlation is taken into account by means of the ...

The adsorption energies of methane and ethane in zeolites are investigated with ab initio molecular orbital theory and density functional theory. In this work we have used zeolite cluster models containing two, three, and five tetrahedral (Si, Al) atoms and have found equilibrium structures for complexes of methane, ethane, and propane with an acid site. ...

We outline two complementary approaches based on the no core shell model (NCSM) and present recent results. In the ab initio approach, nuclear properties are evaluated with two-nucleon (NN) and three-nucleon interactions (TNI) derived within effective field theory (EFT) based on chiral perturbation theory (ChPT). Fitting two available ...

Ab initio calculations are performed to probe the hydrogen bonding, structural, and superconducting behaviors of HBr and HCl under high pressure. The calculated results show that the hydrogen bond symmetrization (Cmc21-->Cmcm transition) of HBr and HCl occurs at 25 and 40 GPa, respectively, which can be attributed to the symmetry stretching A1 mode ...

Non-covalent interactions involving aromatic rings contribute significantly to the stability of three-dimensional structures of biological macromolecules. Therefore, accurate descriptions of such interactions are crucial in understanding the functional mechanisms of biological molecules. However, it is also well known that, for some cases where van der Waals interactions make a dominant ...

A detailed study of methods for generating the minimum energy path of a chemical reaction using ab initio electronic structure calculations is presented; the convergence with respect to step size of the geometry and energy along this path is studied with several algorithms. The investigations are extended to the calculation of chemical reaction rate ...

Theoretical Insight into the Interactions of TMA-Benzene and TMA-Pyrrole with B3LYP Density theoretical investigation of the tetramethylammonium(TMA)-benzene and TMA-pyrrole complexes has been performed density in the 5 6 aromatic system of pyrrole is larger than that in the 6 6 system of benzene

to Shirley,17 the peaks were deconvoluted using the CASA-XPS nonlinear least-squares software.18 III. ABCy /Si(001) alloy layers. The calculations were carried out using the Vienna ab initio simulation package VASP 19 which employs ultrasoft Vanderbilt-type pseudopotentials20 and a plane-wave basis set

Auger and Coster--Kronig transition probabilities have been calculated ab initio relativistically from perturbation theory, for frozen orbitals, in the Dirac--Hartree--Slater approach. Results in the j-j coupling scheme are tabulated for > or =22 elements with atomic numbers 18< or =Z< or =96.

Auger and Coster-Kroing transition probabilities have been calculated ab initio relativistically from perturbation theory, for frozen orbitals, in the Dirac-Hartree-Slater approach. Results in the j-j coupling scheme are tabulated for 22 elements with ato...

We demonstrate a probe for nearest-neighbor correlations of fermionic quantum gases in optical lattices. It gives access to spin and density configurations of adjacent sites and relies on creating additional doubly occupied sites by perturbative lattice modulation. The measured correlations for different lattice temperatures are in good agreement with an ...

Van der Waals broadening coefficients for numerous spectral transitions and radiator-perturber pairs are estimated by semi-empirical methods. The results are verified by ab initio electronic structure calculations and available experimental data. At the same time this allows to establish the range of applicability of Van der Waals ...

Accurate calculations for the H-(H20) complex with extended basis sets are reported at the restricted Hartree-Fock (RHF) through the fourth-order Moller-Plesset (MP) perturbation levels of theory. In the equilibrium geometry of the H-(H2O) complex the H- ...

Unscreened Hartree-Fock approximation (HFA) calculations for metallic Fe, Co, Ni, and Cu are presented, by using a quantum-chemical approach. To the best of our knowledge these are the first HFA results to have been done for crystalline 3d transition metals. Our approach uses a linearized muffin-tin orbital calculation to determine Bloch functions for the Hartree one-particle Hamiltonian, and from ...

We develop a new ab initio many-body approach ootnotetextS. Quaglioni and P. Navratil, arXiv:0804.1560. capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method ootnotetextY. C. Tang et al., Phys. Rep. 47, 167 (1978); K. Langanke and H. Friedrich, Advances in ...

One of the greatest challenges of nuclear physics today is the development of a quantitative microscopic theory of low-energy reactions on light nuclei. At the same time, technical progress on the theoretical front is urgent to match the major experimental advances in the study of exotic nuclei at the radioactive beam facilities. We build a new ab initio ...

It is shown how many-body perturbation theory may be applied to the problem of correcting Hartree-Fock energies and wave functions for the degenerate ground states of open-shell atoms. The choice of an appropriate potential for the calculation of the sing...

A new perturbation scheme based on the Barker-Henderson perturbation theory [J. Chem. Phys. 47, 4714 (1967)] is proposed to predict the thermodynamic properties of spherical molecules. Accurate predictions of second virial coefficients and vapor-liquid coexistence properties are obtained for a large variety of potential functions (square well, Yukawa, ...

Ab initio calculations are used to construct an analytical many-body potential for Pb(2+)He(n) and Pb(+)He(n) clusters which accounts for non pairwise additive interactions. The potential surface reproduces the global minima for cluster sizes ranging from n = 1 to n = 16 obtained from explicit ab ...

In this Letter we pose the question of whether a many-body quantum system with a full set of conserved quantities can relax to an equilibrium state, and, if it can, what the properties of such a state are. We confirm the relaxation hypothesis through an ab initio numerical investigation of the dynamics of hard-core bosons on a one-dimensional lattice. ...

The existence of image states in small clusters is shown for the first time, using an ab initio many-body approach. We present image state energies and wavefunctions for spherical jellium clusters up to 186 atoms, calculated in the GW approximation, which by construction contains the dynamic long-range correlation effects that give ...

A simple but accurate and computationally efficient method for routine ab initio calculations of molecular Rydberg states is described. The method, which can be applied to Rydberg states associated with a nondegenerate ion core, consists in the self-consistent solution of an effective one-electron problem. First, the restricted Hartree-Fock problem of the ...

A simple but accurate and computationally efficient method for routine ab initio calculations of molecular Rydberg states is described. The method, which can be applied to Rydberg states associated with a nondegenerate ion core, consists in the self-consistent solution of an effective one-electron problem. First, the restricted Hartree-Fock problem of the ...

A global single-sheeted double many-body expansion potential energy surface is reported for the ground electronic state of N2H2. Starting from an approximate cluster expansion of the molecular potential that utilizes previously reported functions of the same family for the triatomic fragments, four-body energy terms have been calibrated from extensive accurate ...

We discuss peculiarities of open-quantum systems, as compared to closed-quantum systems. We emphasize the importance of taking continuum degrees of freedom into account when dealing with systems with a tendency to decay through emission of fragments. In this context, we introduce the coupled-cluster theory and argue that this method allows for an accurate description of such systems starting from ...

A number of advances in the theory of x-ray absorption (XAS) have been developed with the aim of achieving a parameter-free treatment of the key many-body effects.footnotetextJ. J. Rehr et al., Comptes Rendus Physique, 10, 548 (2009) These include a GW many-pole self-energy model, ab initio Debye-Waller factors, and an RPA screened ...

In this work, the goals are to explore the potential of different structural energetic materials that are made from different combinations of reactive materials, different binders and voids. In such exploratory studies, it is necessary to consider different ratios of the basic ingredients. Because the dual functional energetic structural materials are used in applications where the resulting ...

... states into the state of interest. This phenomenon is termed spin contamination. A ... (ROHF) which is an eigenfunction of spin. ...

High-level ab initio calculations were carried out to evaluate the interaction between the hydroquinone and benzene molecules. The intermolecular interaction energy was calculated using the M�ller-Plesset second-order perturbation theory at the complete basis set limit and also at the coupled cluster theory with single, double, and ...

We suggest a theoretical model for calculating the matrix perturbation on the spectra of atoms trapped in rare gas systems. The model requires the ''potential curves'' of the diatomic system consisting of the trapped atom interacting with one from the matrix and relies on the approximation that the total matrix ...

The heats of formation of CF3, its cation and anion, CF4, C2F4, and :CFCF3 have been calculated at high levels of ab initio molecular orbital theory. Geometries and frequencies were determined, in general, with second-order perturbation theory. Total energies based on coupled cluster calculations with perturbative ...

... energies including valence-shell electron correlation were obtained from many-body perturbation theory (MBPT) for diborane, borane carbonyl ...

With the aim of searching for conformational signatures in valence x-ray photoionization spectra (XPS) of polyoxymethylene, Many-body Green's function calculations have been conducted at the second-order and diagonal 2ph-TDA levels of approximation on simple oligomers CH3-O-(CH2-O-)x -CH3 where x = 1, 2, 3, and 4. Variations observed in the shape of spectral bands are related ...

We report a fragment-based electronic structure method, intended for the study of clusters and molecular liquids, that incorporates electronic polarization (induction) in a self-consistent fashion but treats intermolecular exchange and dispersion interactions perturbatively, as post-self-consistent field corrections, using a form of pairwise symmetry-adapted ...

We report a fragment-based electronic structure method, intended for the study of clusters and molecular liquids, that incorporates electronic polarization (induction) in a self-consistent fashion but treats intermolecular exchange and dispersion interactions perturbatively, as post-self-consistent field corrections, using a form of pairwise symmetry-adapted ...

We describe an ab initio approach to compute the optical absorption spectra of molecules and solids, which is suitable for the study of large systems and gives access to spectra within a wide energy range. In this approach, the quantum Liouville equation is solved iteratively within first order perturbation theory, with a Hamiltonian ...

The quantum mechanical theory for the scattering of two identical rigid rotors is reviewed and applied to the collision of O2(3Sigma(g)-) molecules using a new accurate ab initio potential energy surface (PES) for the quintet state of the composite system. The PES is based on calculations using restricted coupled-cluster theory with singles, doubles, and ...

The quantum mechanical theory for the scattering of two identical rigid rotors is reviewed and applied to the collision of O2(3?g-) molecules using a new accurate ab initio potential energy surface (PES) for the quintet state of the composite system. The PES is based on calculations using restricted coupled-cluster theory with singles, doubles, and ...