... Abstract : Results are presented from ab initio quantum chemical calculations on the ground state potential energy surface for the open shell ...
DTIC Science & Technology
... Accession Number : ADA351780. Title : Ab Initio and DFT Potential Energy Surfaces for Cyanuric Chloride Reactions. Descriptive Note : Final rept. ...
... Accession Number : ADA270577. Title : Ab Initio Potential Energy Surface for the H + OCS Reaction. Descriptive Note : Final rept. ...
... [2"- ARMY RESEARCH LABORATORY [C Ab Initio Potential Energy Surface for H + OCS Reactions: Extended Basis Sets ...
We report on the determination of a high quality ab initiu potential energy surface (PES) and dipole
NASA Technical Reports Server (NTRS)
A simple method is described to adjust a potential energy surface to improve agreement with experiment. An application is made to the ab initio HCO potential energy surface.(AIP)
Energy Citations Database
... Results of this study substantiate findings from an earlier quantum chemical study using a lower ... for (I) and (II) based on the earlier ab initio study. ...
We have carried out extensive high quality ab initio electronic structure calculations of the ground
... the potential energy surface provided by modern electronic structure ... screening approach, to determine the equilibrium geometry and composition ...
The results of an ab initio calculation of the potential energy surface governing atomic hydrogen recombination in the presence of helium atoms are presented. (auth)
... eg, SiHl6= has a negative ionization potential. ... V. POTENTIAL ENERGY SURFACES AND DYNAMICS ... initio with effective core potentials, ab initio ...
The predissociation line broadening in the Schumann-Runge bands of O2 is explained by an ab initio calculation of the pertinent repulsive potential energy curves and spin-orbit matrix elements. The ab initio results provide an overall qualitative picture ...
National Technical Information Service (NTIS)
In the present work we shall discuss recent advances in quantum chemical methodology that have improved the reliability of ab initio electronic structure ...
NASA Website
control of molecular dynamics; grid methods in the solution of time-dependent problems in quantum mechanics; ab initio calculation of potential energy surfaces and vibronic...
Science.gov Websites
... The structures of the entrance channel transition states show the four-body intermediates ... Campus Box 427 Boulder, CO 80309-0427 ...
... Title : A Comparative Study of Nonlocal Density Functional Theory and ab initio Methods: The Potential Energy Surface of sym-Triazine Reactions. ...
We study the potential energy landscape underlying the motion of monatomic liquids by quenching from random initial configurations (stochastic configurations) to the nearest local minimum of the potential energy. We show that this procedure reveals the underlying potential ...
with molecular dynamic simulations in combination with high level correlated ab initio quantum chemical the existing minima in the PES. 2. Ab initio quantum-chemical calculations. The lowest energy minima (within surface analysis by metadynamics. Gibbs energies and populations obtained from ab ...
E-print Network
Results are presented from ab initio quantum chemical calculations on the ground state potential energy surface for the open shell doublet reaction: HNO + NO right arrow N2O + OH. (I) This reaction is thought to be Important in the sustained combustion of...
Accurate quartet- and doublet-state potential-energy surfaces for the interaction of a hydrogen atom and an oxygen molecule in their ground states have been determined from an ab initio calculation using large-basis sets and the internally contracted mult...
Ab initio calculations using extended basis sets are presented for the potential energy surface (PES) of H + OCS. There are two major reaction channels on the PES; Reaction (I) is H(2S) + OCS(1(Sigma)) yields OH(2(Pi)) + CS(1(Sigma)), and Reaction (II) is...
We report a highly correlated multireference configuration interaction calculation of the near-equilibrium potential energy surface of ozone using a large correlation consistent basis set. Three-dimensional analytical expressions are obtained for the potential energy and dipole moment functions using least-squares ...
An approach is developed to enhance sampling for ab initio Monte Carlo and ab initio path integral Monte Carlo calculations of molecular clusters by utilizing an approximate potential as a guide to move in the configuration space more efficiently. The interpolated potential ...
PubMed
A new exchange-Coulomb semiempirical model potential energy surface for the He-N2 interaction has been developed. Together with two recent high-level ab initio potential energy surfaces, it has been tested for the reliability of its predictions of second-virial coefficients ...
NASA Astrophysics Data System (ADS)
The lowest two ab initio potential energy surfaces (PES), and the corresponding nonadiabatic couplings between them, have been obtained for the H{sub 3}{sup +} system; the molecular data are compared to those calculated with the diatomic in molecules (DIM) method. The form of the couplings is discussed in terms of ...
A practical method of calculating the intrinsic reaction coordinate starting at a saddle point is proposed. The method has been used in combination with the analytical evaluation of the energy gradient for the calculation of the reaction coordinate on an ab initio potential energy surface. The reaction coordinates ...
The recombination dynamics for the SiH2 +SiH2 = SiH2 reaction are studied by quasiclassical trajectory methods using a global potential-energy surface fitted to the available experimental data and the results of various ab initio calculations. The potenti...
Dynamical calculations are performed on an ab initio potential energy surface for KCN. Approximate variational solutions of the vibrational Eckart hamiltonian are presented for several states. Fundamental vibrations are found to lie at 302�7 cm-1 and 119�7 cm-1. An effective rotational hamiltonian is solved for ...
The potential energy surfaces for the doublet pi and doublet sigma states in the collinear F+HH reaction have been calculated with ab initio restricted Hartree-Fock (GRHF) and GRHF-CI (configuration interaction) methods. The doublet pi state in the CI cal...
Ab initio and nonlocal density functional theory (DFT) calculations were performed to determine reaction mechanisms for formation of the six- membered ring C3N3Cl3 (cyanuric chloride) from the monomer, cyanogen chloride (ClCN). MP2 geometry optimizations ...
Ab Initio electronic structure calculations using analytical energy derivative methods and automated potential energy surface walking techniques have been carried out on the tautomerization reaction path connecting formamide (F) H2N-CHO, through a transit...
X. Huang, B.J. Braams, J.M. Bowman, R.E.A. Kelly, J. Tennyson, G.C. Groenenboom, and Ad van der Avoird : New ab initio potential energy surface and ...
The unimolecular dissociation dynamics of disilane are investigated using classical trajectory methods with a global potential-energy surface fitted to the available experimental data and the results of various ab initio calculations. The potential surfac...
The potential energy surface for trimers of hydrogen fluoride is examined for multiple arrangements of the three-molecule cluster. Several established approaches to model the potential energy are examined, including a strictly pairwise additive potential, an established polarizable potential model, another, ...
Rich reactive resonances are found in a 3D quantum dynamics study of the N + N2 exchange reaction using a recently developed ab initio potential energy surface. This surface is characterized by a feature in the interaction region called Lake Eyring , that...
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)
The addition and abstraction reaction pathways on the potential energy surface for H + HCO have been characterized by an ab initio four electron, complete active space, self-consistent field electronic structure calculation. The elimination pathway to go ...
The HNO molecule is of interest in both combustion and atmospheric chemistry. For example, Guadagnini et al. have recently presented ab initio potential energy surfaces for the three lowest lying electronic states of HNO and then used these in examining s...
Dynamics of the O( ) + HCl reaction on the electronic state: A new ab initio potential energy for the lowest electronic state of the O( ) + HCl system is presented. This surface is based on electronic the reactants O( ) + HCl() to the products OH() + Cl( ). The reaction barrier on this surface lies at an O
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The rates of intramolecular proton transfer are calculated on a full-dimensional reactive electronic potential energy surface that incorporates high level ab initio calculations along the reaction path and by using classical Transition State theory, Path-Integral Quantum Transition State Theory, and the Quantum ...
PubMed Central
Variational transition state theory calculations with the correction of multidimensional tunneling are performed on a 12-dimensional ab initio potential energy surface for the H+SiH4 abstraction reaction. The surface is constructed using a dual-level strategy. For the temperature range 200-1600 K, thermal rate ...
Potential energy curves for electronic states of Hg/sub 2/ and TlHg are presented and analyzed. They are derived using large scale configuration interaction procedures for the valence electrons, with the core electrons represented by ab initio relativistic effective potentials. The effect of spin-orbit coupling are ...
The potential energy surface of the ground state of the He-MnH(X (7)Sigma(+)) van der Waals complex is presented. Within the supermolecular approach of intermolecular energy calculations, a grid of ab initio points was computed at the multireference configuration interaction level using the aug-cc-pVQZ basis set ...
An analytic function for the ground-electronic-state HCO {yields} H + CO potential energy surface is presented. Both experimental and ab initio data are used to derive parameters for the potential energy surface. Bound-state eigenvalues are obtained, and the results show ...
The interaction of CO{sub 2} and water is investigated by a combination of ab initio and SOLDRI-MM2 techniques. Ab initio results at levels of theory as high as MP2/6-311+G**//6-31G** are found to be in reasonable agreement with experiment. The R.{theta} potential energy ...
Structural and thermal properties of small lithium clusters are studied using ab initio-based Monte Carlo simulations. The ab initio scheme uses a Hartree-Fock/density functional treatment of the electronic structure combined with a jump-walking Monte Carlo sampling of nuclear configurations. Structural forms of ...
Critical points on the potential energy surface (PES) for sym-triazine (C3N3H3) have been calculated using nonlocal density functional (NDFT) methods. The two decomposition mechanisms for sym-triazine investigated are a concerted triple dissociation of th...
A new global potential energy surface for the lowest triplet electronic state (a(3)A") of HNO has been developed by a three-dimensional cubic spline interpolation of more than 13,000 ab initio points, which were calculated at the multireference configuration interaction level with Davidson correction using the ...
A new high quality three-dimensional potential energy surface for the Ne-CO van der Waals complex is developed using the CCSD(T) method and avqz/avqz+33221 basis set. The ab initio calculation is performed in a total of 1365 configurations with supermolecule method. There is a single global minimum located in a ...
A new global potential energy surface for the lowest triplet electronic state (a3A'') of HNO has been developed by a three-dimensional cubic spline interpolation of more than 13 000 ab initio points, which were calculated at the multireference configuration interaction level with Davidson correction using the ...
The interaction potential energy surface (PES) of H{sub 4} is of great importance for quantum chemistry, as a test case for molecule--molecule interactions. It is also required for a detailed understanding of certain astrophysical processes, namely, collisional excitation and dissociation of H{sub 2} in molecular clouds, at densities too low to be ...
-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 ...
The potential energy curve of the molecular negative ion CN is constructed by morphing an accurate ab initio potential to available rotational data [C.A. Gottlieb, S. Br�nken, M.C. McCarthy, P. Thaddeus, J. Chem. Phys. 126 (2007) 191101] within the framework of the reduced potential curve approach of Jen? [F. ...
A three-dimensional potential energy surface has been calculated for the ground electronic state of the HOCO+-He system. The calculations were performed at the coupled electron pair approximation level with an extended basis set which ensures a balance between accuracy and feasability. The validity of the method and of the basis set was tested through ...
An efficient procedure based on the reproducing kernel Hilbert space interpolation method is presented for constructing intermolecular potential energy surfaces (PES) using not only calculated ab initio data but also a priori information on long-range interactions. Explicitly, use of the reciprocal power ...
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 ...
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 ...
Ab initio molecular electronic structure theory has now progressed to the point where it is capable of making genuine contributions to the understanding of simple chemical reactions. Especially noteworthy examples are the elementary fluorine hydrogen reactions pertinent to the HF chemical laser. The reactions F + H/sub 2/ ..-->.. FH + H, H + FH ...
This paper discusses using kinetic, spectroscopic, and ab initio studies of the prooxidant reaction of vitamin E derivatives to determine second-order rate constants for the reaction of six tocopheroxyl radicals with five alkyl hydroperoxides in benzene along with the first adiabatic ionization potentials of the alkyl hydroperoxides. These results suggest ...
The study and prediction of chemical reactivity is one of the most influential contributions of quantum chemistry. A central concept in the theoretical treatment of chemical reactions is the reaction pathway, which can be quite difficult to integrate accurately and efficiently. This talk will outline our developments in the integration of these pathways on ab ...
The quantum dynamics of the rotational quenching of the Mg24H+(X1?+) molecular cation interacting with He4(1S) as a buffer gas, at relative temperatures ranging from 1 K down to millikelvins, is described by accurate close coupling scattering calculations on an ab initio potential energy surface. The efficiency of ...
A new ab initio potential energy surface of the Ne�CO complex is developed using single and double excitation coupled-cluster theory with noniterative treatment of triple excitations [CCSD(T)]. The potential has a minimum value of ?49.396 cm?1 at Re = 6.40a0 with approximately T-shaped geometry (?e = 82.5�). ...
The photoelectron spectra of the weakly bound KrO- anion are simulated using a theory which combines the atoms-in-molecule model for molecular electronic wave functions and the Rau-Fano model for photodetachment intensities [J. Chem. Phys. 112, 5852 (2000)]. The nonrelativistic potential energy curves of the anion are obtained from ab ...
The desorption potential energies of a hydrogen molecule from hydrogenated diamond C(100) surfaces have been calculated by the ab initio pseudopotential method.We found that a dihydride surface is less stable than a monohydride surface and that hydrogen desorption can be expected to occur from the dihydride instead ...
Mass tensor molecular dynamics method was first introduced by Bennett [J. Comput. Phys. 19, 267 (1975)] for efficient sampling of phase space through the use of generalized atomic masses. Here, we show how to apply this method to ab initio molecular dynamics simulations with minimal computational overhead. Test calculations on liquid water show a threefold ...
The nature of intermolecular interactions between aromatic amino acid residues has been investigated by a combination of molecular dynamics and ab initio methods. The potential energy surface of various interacting pairs, including tryptophan, phenilalanine, and tyrosine, was scanned for determining all the ...
Structure and dynamics of HeI2 van der Waals (vdW) complex are analyzed from first principles. Ab initio technology, at CCSD(T) and MRCI level of theories, was employed for constructing potential energy surfaces of the ground and excited electronic states, and a full quantum mechanical treatment for studying its ...
We present pair potentials for fluorinated methanes and their dimers with CO2 based on ab initio potential energy surfaces. These potentials reproduce the experimental second virial coefficients of the pure fluorinated methanes and their mixtures with CO2 without adjustment. Ab ...
A biased potential molecular dynamics simulation approach, accelerated molecular dynamics (AMD), has been implemented in the framework of ab initio molecular dynamics for the study of chemical reactions. Using two examples, the double proton transfer reaction in formic acid dimer and the hypothetical adiabatic ring opening and subsequent rearrangement ...
Recent accurate observations [1] of collision-induced absorption (CIA) in the nitrogen and oxygen fundamentals pointed at the existence of the minimum in its integrated intensity temperature variation. This work aims at simulation of the CIA intensity in N2 using quantum chemical complete potential energy and dipole surfaces for N2-N2 system. The absolute ...
A new global potential energy surface is reported for the ground state (4A'') of the reaction H(2S) + NH(X3?-) --> N(4S) + H2 from a set of accurate ab initio data, which were computed using the multi-reference configuration interaction with a basis set of aug-cc-pV5Z. The many-body expansion and neural network ...
A new global potential energy surface is reported for the ground state ((4)A(")) of the reaction H((2)S) + NH(X(3)?(-)) ? N((4)S) + H(2) from a set of accurate ab initio data, which were computed using the multi-reference configuration interaction with a basis set of aug-cc-pV5Z. The many-body expansion and neural ...
A semiempirical potential energy surface is obtained for the major isotopologue of the water molecule H2 16O that allows the vibration-rotation energy levels in the range of 0-26000 cm-1 to be calculated with an accuracy almost equal to the average experimental accuracy of measurements in the infrared and visible ranges. Variational calculations using this ...
Ab initio global adiabatic and quasidiabatic potential energy surfaces of lowest four electronic (1-4? (3)A(")) states of the H(+)+O(2) system have been computed in the Jacobi coordinates (R,r,?) using Dunning's cc-pVTZ basis set at the internally contracted multireference (single and double) configuration ...
Ab initio global adiabatic and quasidiabatic potential energy surfaces of lowest four electronic (1-4 3A'') states of the H++O2 system have been computed in the Jacobi coordinates (R,r,?) using Dunning's cc-pVTZ basis set at the internally contracted multireference (single and double) configuration interaction ...
A quantum mechanical investigation of the vibrational and rotational deactivation of NO(+) in collisions with He atoms in the cold and ultracold regime is presented. Ab initio potential energy calculations are carried out at BCCD(T) level and a new global 3D potential ...
A quantum mechanical investigation of the vibrational and rotational deactivation of NO+ in collisions with He atoms in the cold and ultracold regime is presented. Ab initio potential energy calculations are carried out at BCCD(T) level and a new global 3D potential energy ...
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. ...
In the present work, all adiabatic potential energy curves, spectroscopic constants and dipole moments of CaH+ molecular ion dissociating below the ionic limit Ca2+H- are presented. These curves are determined by an ab initio approach involving a non-empirical pseudo-potential for the Ca core, core-valence ...
... This study involves: Ab-initio crystal orbitals and polymer orbitals; Ab-initio coupled cluster program; Ab-initio quantum chemical calculations and ...
Four potential energy surfaces are of current interest for the Ne-CO interaction. Two are high-level fully ab initio surfaces obtained a decade ago using symmetry-adapted perturbation theory and supermolecule coupled-cluster methods. The other two are very recent exchange-Coulomb (XC) model ...
The interaction potential energy surface (PES) of H4 is of great importance for quantum chemistry as a test case for molecule-molecule interactions. It is also required for a detailed understanding of certain astrophysical processes, namely collisional excitation and dissociation of H2 in molecular clouds, at densities too low to be accessible ...
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 ...
Double proton transfer (DPT) reaction of a 7-azaindole dimer in the first ??* electronically excited state was studied theoretically. We investigated the reaction mechanism through constructing a full dimensional empirical valence bond potential energy function (PEF) based on potential energies evaluated by ...
In a previous publication (1997. P. Jensen, J. Mol. Spectrosc. 181, 207-214), rotation-vibration energy levels for the electronic ground state X3B1 of the amidogen ion, NH2+, were predicted using the MORBID Hamiltonian and computer program with an ab initio potential energy surface. In the present paper we ...
An automatic procedure for the generation of potential energy surfaces based on high level ab initio calculations is described. It allows us to determine the vibrational wave functions for molecules of up to ten atoms. Speedups in computer time of about four orders of magnitude in comparison to standard ...
The authors study the photodissociation reactions of pyrrole and N-methylpyrrole using first-principles molecular dynamics. The first excited state is described with restricted open-shell Kohn-Sham theory. They find a small barrier in the excited state potential energy surface. The possibility of energy redistribution near the Franck-Condon region leads to ...
Zinc crystallizes in the hcp structure, but with an anomalously large c/a ratio, indicating a strong distortion away from ideal packing. Coupled cluster calculations within the framework of the method of increments, improved by an embedding scheme for metals, were performed to explore the potential energy surface of zinc with respect to the hexagonal ...
Rotational and rovibrational transitions with parity doublings and hyperfine structures of the Ne-NO complex in the electronic ground state have been observed by Fourier-transform microwave spectroscopy, and they are analyzed by employing a free-rotor model with a standard deviation of the least-squares fit to be 12 kHz. A 2-dimensional intermolecular potential ...
Extensive ab initio configuration interaction calculations have been carried out for different directions of approach of a proton to a rigid acetylene molecule. The calculated potential energy curves of several singlet states are presented. The anisotropy we found allows us to explain features of the charge ...
A series of stationary structures of the hydrazinyl radical have been characterized by optimization at the CCSD(T)/cc-pVTZ level of theory. CCSD(T)/aug-cc-pVXZ single-point calculations have also been carried out at the optimized geometries with basis sets of different cardinal numbers (X = T, Q), which were used to obtain accurate energies via extrapolation to the complete basis set limit. A ...
... Title : Chalcopyrite Magnetic Semiconductors: An Ab-Initio Study of Their Structural, Electronic and Magnetic Properties. ...
... 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,. ...
We have applied the ab initio path integral molecular dynamics simulation to study hydronium ion and its isotopes, which are the simplest systems for hydrated proton and deuteron. In this simulation, all the rotational and vibrational degrees of freedom are treated fully quantum mechanically, while the potential ...
We present full-dimensional potential energy surfaces (PESs) for hydrated chloride based on the sum of ab initio (H(2)O)Cl(-), (H(2)O)(2), and (H(2)O)(3) potentials. The PESs are shown to predict minima and corresponding harmonic frequencies accurately on the basis of comparisons with previous and new ...
Quantum chemical calculations of energies, geometrical structure and vibrational wave numbers of 3,4-dimethoxybenzonitrile (DMBN) were carried out by the ab initio Hartree-Fock (HF) and density functional theory (DFT) with complete relaxation in the potential energy surface using 6-311++G(d,p) basis set. The ...
The molecular vibrations of xanthine were investigated in polycrystalline sample, at room temperature by Fourier transform infrared (FTIR) and FT-Raman spectroscopies. The spectra of the molecule have been recorded in the regions 4000-50 cm(-1) and 3500-100 cm(-1), respectively. Theoretical information on the optimized geometry, harmonic vibrational frequencies, infrared and Raman intensities were ...
We present elastic and inelastic spin-changing cross sections for cold and ultracold NH(X (3)?(-)) + NH(X (3)?(-)) collisions, obtained from full quantum scattering calculations on an accurate ab initio quintet potential-energy surface. Although we consider only collisions in zero field, we focus on the cross sections relevant for ...
We present elastic and inelastic spin-changing cross sections for cold and ultracold NH(X 3?-) + NH(X 3?-) collisions, obtained from full quantum scattering calculations on an accurate ab initio quintet potential-energy surface. Although we consider only collisions in zero field, we focus on the cross sections relevant for magnetic ...
Molecular dynamics simulations of NO-doped Ar solid upon Rydberg photoexcitation of the impurity have been carried out taking into account angular dependent potential energy surfaces (PESs) in the ground and excited states. To go beyond isotropic potentials simulations, the effects of anisotropy of potentials on the structure, dynamics, and energetics are ...
Three-dimensional quantum mechanical calculations on the vibrational predissociation dynamics of HeI2 B state complex are performed using a potential energy surface accurately fitted to unrestricted open-shell coupled cluster ab initio data, further enabling extrapolation for large I2 bond lengths. A Lanczos ...
We perform ab initio calculation using quantum chemistry package (MOLPRO) on the excited states of Na(3) cluster and present the adiabatic PESs for the electronic states 2(2)E' and 1(2)A(1)', and the non-adiabatic coupling (NAC) terms among those states. Since the ab initio calculated NAC elements for the states ...
We perform ab initio calculation using quantum chemistry package (MOLPRO) on the excited states of Na3 cluster and present the adiabatic PESs for the electronic states 22E' and 12A1', and the non-adiabatic coupling (NAC) terms among those states. Since the ab initio calculated NAC elements for the states 22E' and ...
A global 12-dimensional ab initio interpolated potential energy surface (PES) for the SiH4+H-->SiH3+H2 reaction is presented. The ab initio calculations are based on the unrestricted quadratic configuration interaction treatment with all single and double excitations ...
Structural and spectroscopic properties of hydrazine, H(2)N-NH(2), it being a floppy or fluxional molecule in a vacuum, are investigated by means of ab initio molecular dynamics, ab initio path integral molecular dynamics, and ab initio ring polymer molecular dynamics ...
, Czechoslovakia Hans JBrgen Aa. Jensen, Poul Jorgensen Departmenl @Chemistry. Aarhus Universrty, DK-8000 Aarhus C binding is mainly electrostatic in origin and is enhanced by the effect of the charge transfer within
In this work, we introduce a new analytical form based on the q-exponential function to build three-dimensional reactive surfaces. The quality of this new function is tested by fitting the ab initio potential energy surface (PES) to the ground state Na+HF reaction. The thermal rate constant and reactive ...
We report the first coordinated stabilization and coupled channel scattering calculations of resonances for a realistic, triatomic molecule, HCO, using a global, {ital ab} {ital initio} potential-energy surface. The two set of calculations are in excellent agreement with each other for the nine resonance energies reported.
A three-dimensional time-dependent quantum dynamics approach using a recently developed ab initio potential energy surface is applied to study ro-vibrational excitation in N+N2 exchange scattering for collision energies in the range 2.1- 3.2 eV. State-to-...
A general expansion is derived for the transition moment between two nondegenerate vibrational states of a polyatomic molecule. This analysis is combined with ab initio surfaces for the potential energy and the dipole moment of water vapor to predict integrated band absorption intensities. Calculations are compared ...
The document discusses work on potential energy surfaces associated with dimers of ethane, H2S and CH4-H2S. Numerous properties for the individual molecules have been determined, some for the first time. The theoretical treatment has been improved so that...
In order to find the equilibrium geometries of molecules and solids and to perform ab initio molecular dynamics, it is necessary to calculate the forces on the nuclei. We present a correlated sampling method to efficiently calculate numerical forces and potential energy surfaces in diffusion Monte Carlo. This ...
Conformational topology of ribose: A computational study Abraham F. Jalbout *, Ludwik Adamowicz the theoretical study of the configurational topology of the ribose molecule. MP2/6-31G** geometry optimiza- tions.V. Keywords: Ribose; MP2; Coupled cluster theory; Ab initio; Potential energy surface 1. Introduction
Quantum state-to-state differential cross sections, along with the absorption spectrum and product internal state distributions, have been calculated for the photodissociation of H(2)O in its B band on a new set of ab initio potential energy surfaces in a diabatic representation. The theoretical attributes are in ...
Quantum state-to-state differential cross sections, along with the absorption spectrum and product internal state distributions, have been calculated for the photodissociation of H2O in its B band on a new set of ab initio potential energy surfaces in a diabatic representation. The theoretical attributes are in ...
New methods which avoid the repeated constructions of aggregate Hamiltonian matrices over antisymmetric basis states generally required in conventional calculations of adiabatic potential energy surfaces are reported for ab initio studies of the structure...
Features of the potential energy surface pertinent to the thermal decomposition mechanism of methylenenitramine (CH(sub 2)NNO(sub 2)) are investigated. At issue are the activation energies both for concerted molecular dissociation leading to HCN and HONO ...
A new semiempirical exchange-Coulomb model potential energy surface for the N2-He interaction was reported recently [A. K. Dham et al., J. Chem. Phys. 127, 054302 (2007)] and, using it, the temperature dependence of bulk gas properties of N2-He mixtures, such as the second virial coefficient and traditional transport phenomena, most of which depend ...
We present a detailed study of the potential energy surfaces of the water dication correlating asymptotically with O((3)P) and O((1)D). Using ab initio multireference configuration interaction method, we computed a large ensemble of data, which was used to generate a fit of each potential ...
Whereas conical intersections between potential energy surfaces of bound states are well known, the interaction of short-lived states has been investigated only rarely. Here, we present several systematically constructed model Hamiltonians to study the topology of intersecting complex potential energy surfaces ...
... Title : AB Initio Study of the Electronic Magnetic Circular Dichroism ... functions are determined using as initio quantum chemical techniques including ...
The multidimensional potential energy surfaces of the peptide chains consisting of three and six alanine (Ala) residues have been studied with respect to the degrees of freedom related to the twist of these molecules relative to the peptide backbone (these degrees of freedom are responsible for the folding of such peptide molecules and proteins). The ...
A new simple analytical diatomic potential energy function that can be considered an extension of the prototypical Lennard-Jones model is proposed and tested. Five- and six-parameter models are considered and these can be easily constructed from widely available low-order vibrational-rotational constants and the dissociation energy. Accuracy tests are ...
The global potential energy surfaces for both the ground (X~1A') and excited (A~1A'') electronic states of the HNO molecule have been constructed by three-dimensional cubic spline interpolation of more than 17 000 ab initio points, which have been calculated at the internal contracted multi-reference configuration ...
A new high quality three-dimensional potential energy surface for the Ne-CO van der Waals complex is developed using the CCSD(T) method and avqz?avqz+33221 basis set. The ab initio calculation is performed in a total of 1365 configurations with supermolecule method. There is a single global minimum located in a ...
