The lifetimes of atomic inner-shell vacancies are uniquely related, through the uncertainty principle, to widths of the corresponding atomic energy levels. In many cases, atomic level widths can be measured quite accurately by x-ray photoelectron spectros...
National Technical Information Service (NTIS)
Accurate atomic lifetime data are useful for terrestrial and astrophysical plasma diagnostics. At accuracies higher than those required for these applications, lifetime measurements test atomic structure theory in ways complementary to spectroscopic energy determinations. At the highest level ...
NASA Astrophysics Data System (ADS)
Energy Citations Database
A number of recent atomic lifetime measurements on multiply charged ions have reported uncertainties lower than 1%. Such a level of accuracy challenges theory, which is a good thing. However, a few lessons learned from earlier precision lifetime measurements on atoms and singly charged ions suggest that one should ...
using time-resolved laser-induced fluorescence in the UV and VUV on an atomic beam of boron. The accurate lifetimes provide a base for improved ...
NASA Website
The DIRAC experiment aims to measure the lifetime of ?+?- atoms in the ground state with 10% precision, using the 24 GeV/c proton beam of the CERN Proton Synchrotron. As the value of the above lifetime of order 10-15s is dictated by a strong interaction at low energy, the precise measurement of this quantity enables to determine a ...
The complex mixtures encountered place a heavy burden on the analytical ... lifetimes accurate to within 10% for systems involving first- and second-row atoms. ... The final examples consider systems involving transition metal atoms, ... in the crater bottoms, along the walls, and on top of the overturned ...
A number of recent atomic lifetime measurements on multiply charged ions have reported uncertainties lower than 1%. Such a level of accuracy challenges theory, which is a good thing. However, a few lessons learned from earlier precision lifetime measurements on atoms and singly charged ions suggest to remain ...
DOE Information Bridge
Radiative lifetimes measured by time-resolved laser-induced fluorescence are reported for 40 odd-parity levels and 36 even-parity levels of singly ionized terbium. The odd-parity levels range in energy from 29000 to 40000 cm{minus}1 and those of even-parity from 21000 to 37000 cm{minus}1. These lifetimes, with one exception, are ...
Lifetimes, oscillator strengths and hyperfine structures in Ho II are measured. Accurate atomic structure data are of importance for element identification in stellar atmospheres as well as in atomic structure studies. Lifetimes of 3 excited levels, all observed in stellar spectra, have been ...
The current work is part of an ongoing study of radiative properties of rare earth neutral atoms motivated by research needs in several disparate fields including astrophysics, laser chemistry and lighting technology. Time-resolved laser-induced fluorescence on a slow atomic beam has been used to measure radiative lifetimes, ...
We use the configuration-interaction method and many-body perturbation theory to perform accurate calculations of energy levels, transition amplitudes, and lifetimes of low-lying states of barium and radium. Calculations for radium are needed for the planning of measurements of parity- and time-invariance-violating effects which are strongly enhanced in ...
Precision measurements of atomic lifetimes are important to the analysis of data from many areas of physics and provide fundamental atomic structure information. Scientists in the fields of astrophysics, geophysics, and plasma fusion all depend on oscillator strengths to determine the relative abundances of elements. Assessing the ...
Financial support of this research project has lead to advances in the study of atomic structure through precision measurements of atomic lifetimes, energy splittings, and transitions energies. The interpretation of data from many areas of physics and chemistry requires an accurate understanding of ...
We present a calculation of the shifts and lifetimes of hydrogen-atom excited states in the vicinity of a jellium surface. The calculations combine accurate density-functional potentials with a complex scaling theory for obtaining resonances by means of bound-state procedures. The lifetimes of the hydrogen levels ...
The technique of time-resolved laser-induced fluorescence is the best method for lifetime measurements because it is largely free from systematic errors that undermine other methods. Lifetime measurements have been performed using time-resolved laser-induced fluorescence on atom and ion beams of many refractory elements including MoI, ...
Radiative lifetimes, accurate to �5%, have been measured for 153 levels of neutral cerium using time-resolved laser-induced fluorescence (TRLIF) on a slow beam of cerium atoms. Of the 153 levels studied, 150 are even parity and 3 are odd parity. The levels range in energy from 16 869 to 28 557 cm?1. This set of Ce I ...
This project has developed a comprehensive and reliable base of accurate atomic structure data for complex many-electron systems. This has been achieved through the use of sensitive data-based parametric systematizations, precise experimental measurements, and supporting theoretical computations. The atomic properties studies involved ...
Transition probabilities of 1191 spectral lines in the first spectra of Nb, Rh, Hf, Ta, and W are determined by accurate measurements of radiative lifetimes and branching ratios. The lifetimes are measured by the time-resolved laser-induced fluorescence on an atomic beam. The atomic beam source ...
A simple model based on the statistics of single atoms is developed to predict the stability or lifetime of nanodevices without empirical parameters. Under certain conditions, the model produces the Arrhenius law and the Meyer-Neldel compensation rule. Compared with the classical molecular-dynamics simulations for predicting the stability of monatomic ...
... Accession Number : ADA150787. Title : Lifetime and Reliability of Rubidium Discharge Lamps for Use in Atomic Frequency Standards. ...
DTIC Science & Technology
Altitude distribution and lifetimes of N atoms and NO molecules from loss process data in atmosphere
NASA Technical Reports Server (NTRS)
The scattering lengths of a two pion system are the golden magnitudes to test the QCD predictions in the low energy sector. The DIRAC (PS-212) experiment at CERN will obtain a particular combination of the S-wave isospin 0 and 2 scattering lengths by measuring the lifetime of pionium, the hydrogen-like ?+?- atom. This measurement tests the ...
An expansion formula for Stark effect transition probabilities is derived in terms of field-free (spherical) transition probabilities. Expansion coefficients are squares of Clebsch-Gordan coefficients from the SO(4) = SU(2) x SU(2) description of the hydrogen atom. The method provides new sum rules for Stark transitions which explain regularities in previous ...
Photoexcitation of long lived xenon 5d[3/2]2 atoms to 5p5, nf', 4 <= n <= 8, autoionizing states has been studied using a crossed-laser fast-atom beam method. Autoionizing features have been analysed using Beutler-Fano lineshapes to provide accurate field-free level positions, lifetimes and line shape ...
Atomic structure calculations were performed for properties such as energy levels, binding energies, transition probabilities, lifetimes, hyperfine structure, and isotope shifts. Accurate computational procedures were devised so that properties could be predicted even when they could not be obtained from experiment, and to assist in ...
The DIRAC experiment aims to measure the lifetime of pi]+[pi- atoms in the ground state with 10% precision, using the 24 GeV/c proton beam of the CERN Proton Synchrotron. As the value of the above lifetime of order 10-15s is dictated by a strong interaction at low energy, the precise measurement of this quantity enables to determine a ...
The spectrum of singly ionized titanium was analyzed by photographic spectral recordings of the light from a hollow cathode. Classified lines in the region 1200 A to 11000 A and term values are reported. Lifetime of the 3p 5 5p levels in neutral argon were measured by the high frequency deflection technique considering the trapping of radiation from the excited 3p 5 4s level. ...
A highly excited (Rydberg) atom bathed in blackbody radiation is perturbed in two ways. A dynamic Stark shift is induced by the off-resonant components of the blackbody radiation. Additionally, electric-dipole transitions to other atomic energy levels are induced by the resonant components of the blackbody radiation. This depopulation effect shortens the ...
Accurate atomic collision and structure data are an essential ingredient for a wide range of research fields as well as for major technological applications. Areas from laboratory physics to quantum processing, from plasma research applications in nuclear fusion to lighting research, as well as astrophysics and cosmology, depend critically on such data. ...
... in the Magnetic Trapping Mode: Mass Spectrometry, Atomic Lifetime Measurements, and Charge Transfer Reactions of Highly Charged Atomic ...
... ATOMIC STATES AND ITS APPLICATION TO HELIUM BY THOMAS M. HOLZ:3ERLEIN ... ATOMIC STATES AND ITS APPLICATION TO HELIUM BY ...
The DIRAC experiment at CERN has been measuring the lifetime of the pionium atom, a bound state of a ?+ and ?- meson. The isospin 0 and 2 scattering length difference will be determined unambiguously once the value of the lifetime is known. In what follows we describe the experimental goals and the first results.
Atomic properties of multiply charged ions have been investigated using excitation of energetic heavy ion beams. Spectroscopy of excited atomic transitions has been applied from the visible to the extreme ultraviolet wavelength regions to provide accurate atomic structure and transition rate data in selected highly ...
... Title : DETERMINATION AND APPLICATION OF ABSOLUTE TRANSITION PROBABILITIES AND LIFETIMES OF ATOMS, MOLECULES, AND IONS ...
A quantitative determination of 2s vacancy lifetimes in surface and bulk atoms of free Ne clusters has been made. While for free atoms the 2s inner-valence hole has a ps lifetime, it reduces to 6+/-1 fs for cluster bulk atoms. For surface atoms, the ...
PubMed
The first three electronically excited states in the alkaline-earth-metal atoms magnesium, calcium, and strontium comprise the (nsnp){sup 3}P{sub J}{sup o}(J=0,1,2) fine-structure manifold. All three states are metastable and are of interest for optical atomic clocks as well as for cold-collision physics. An efficient technique--based on a physically ...
guide, LED Luminaire Lifetime: Recommendations for Testing and Reporting (PDF 666 KB), details specific guidance for accurate reporting of lifetime. Additional metrics...
Science.gov Websites
The results of various studies concerning the lifetime and reliability of the rubidium discharge lamp used in the rubidium atomic frequency standards are reported. The primary life-limiting process in these lamps involves diffusion of the rubidium atoms i...
Atomic properties involving the low-lying excited {sup 2}D{sub 3/2,5/2} states in alkaline-earth-metal ions are of current interest in many different applications ranging from tests of physics beyond the standard model to astrophysics. We have used the relativistic coupled-cluster theory to perform accurate calculations of the ...
& Secretary of the Department of Atomic Energy), received the first ever "Lifetime Reliability Achievement Awards" from the Indian Society of Reliability, Maintainability and...
... Station-keeping systems with lifetimes of thousands ... Metastable Lifetime in Xenon,� Physical Review ... atomic hydrogen emission (Balmer and Lyman ...
We have captured ^210Fr atoms in an on-line magneto-optic trap (MOT) at the superconducting LINAC of Stony Brook. Fr has been identified as a viable candidate for a parity non-conservation measurement. We present here the precision measurement of the 7p ^2P_1/2 state lifetime in atomic Fr and compare the extracted radial matrix ...
This paper discusses the influence of polarization plasma effects on the lifetime of metastable atomic levels. It is shown that plasma effects can also be important in the case when the distance between the metastable level and the closest emitting level exceeds the Langmuir frequency. The lifetime of the 2S level of a hydrogen ...
SummaryCell adhesion is essentially mediated by specific interactions between membrane receptors and ligands. It is now apparent that the mere knowledge of the on- and off-rate of association of soluble forms of these receptors and ligands is not sufficient to yield accurate prediction of cell adhesive behavior. During the last few years, a variety of complementary techniques ...
PubMed Central
Chiral perturbation theory predicts the lifetime of pionium, a hydrogen-like pgr+pgr- atom, to better than 3% precision. The goal of the DIRAC experiment at CERN is to obtain and check this value experimentally by measuring the break-up probability of pionium in a target. In order to accurately measure the lifetime ...
The effect of the meson strong interaction on the properties of the mesic atoms ..pi pi.. and K..pi.. (the lifetime, the energy levels, and the wave function ) is studied. The main result of the study is the determination of a relation between the chiral Lagrangian parameters and the lifetimes of the ..pi pi.. and K..pi.. ...
Within the framework of nonrelativistic quantum mechanics, the analysis of the two-photon absorption by atomic hydrogen is generalized to the case of two incident beams with arbitrary direction and polarization. In the dipole approximation, exact calculation of the angular part of the second-order matrix element responsible for two-photon absorption predicts that, for the s-s ...
The accurate determination of atomic masses and the high-precision measurement of the bound-electron g factor are prerequisites for the determination of the electron mass, which is one of the fundamental constants of nature. In the 2002 CODATA adjustment [P.J. Mohr, B.N. Taylor, Rev. Mod. Phys. 77 (2005) 1], the values of the electron mass and the ...
Atomic transition probabilities for 2874 lines of the first spectrum of cerium (Ce I) are reported. These data are from new branching fraction measurements on Fourier transform spectra normalized with previously reported radiative lifetimes from time-resolved laser-induced-fluorescence measurements (Den Hartog et al 2009 J. Phys. B: At. Mol. Opt. Phys. 42 ...
atomic clock depends on the observationof a particular resonance in cesium atoms. The atoms atomic clocks commcr- cially. The most accurate commercialdevices are based on a resonance technique advances and techniques are im- proving the accuracy of atomic clocks. The ...
E-print Network
The compact scintillator device WILLI, set up in IFIN-HH Bucharest (44� 26' N latitude and 26� 04' E longitude), has been used for measurements of the charge ratio in the atmospheric muon flux. The experimental method, based on the observation of the reduced effective lifetime of negative muons stopped in matter, as compared with the lifetime of ...
The goal of the DIRAC experiment at CERN (PS212) is to measure the ?+?- atom lifetime. Based on part of the collected data we present a first result on the lifetime, ? = <=ft[2.91+0.49-0.62; ] � 10-15 s, and discuss the major systematic errors. This lifetime corresponds to ? a0 - a2? = 0.264+0.033-0.020\\ ...
... HOT GASES, ATOMIC SPECTROSCOPY, LAMINAR FLOW, HEIGHT, VAPORIZATION, PHOTOMETRY, ATOMIZATION, ALKALINE EARTH ...
The lifetimes of rubidium atoms in a dark magneto-optical trap are measured at different populations of the 'bright' and 'dark' hyperfine states of captured atoms. It is found that the lifetime of atoms in the trap decreases if they spend more time in the ...
the third area, the lifetime description of sodium atoms in the ...... It should be emphasized that the expression (21) is not, ...
... Abstract : Atomic physics Lifetime of the metastable state of singly ionized helium Optical detection of level crossings Coherence time ...
... (Author). Descriptors : *NEON, *LINE SPECTRA, ATOMIC ENERGY LEVELS, LIFE EXPECTANCY(SERVICE LIFE), MATHEMATICAL MODELS. ...
... time-resolved emission spectroscopy techniques in ... Descriptors : (* FLUORESCENCE, SCIENTIFIC RESEARCH ... Subject Categories : ATOMIC ...
... LIFE), *LASER INDUCED FLUORESCENCE, *EXCITATION, FLUORESCENCE, ELECTROOPTICS, SODIUM, QUENCHING, GASES, TIME ...
The ionization of the hydrogen atom by an external electrostatic field is reconsidered by taking into account the interaction of the system with the measuring apparatus. The result obtained shows a dependence of the life-time on the frequency of the measu...
Fluorescence emitted by an atom near a metal surface and the coupling of the surface plasmon field of a dielectric substrate to a molecular electronic transition are studied. Explicit expressions for the atomic and molecular lifetimes are derived. It is s...
and Atomic Physics (LCAP) program. Current work in .... Vibration testing mainly relates to the launch on the shuttle, while lifetime issues speak mainly ...
We conduct a systematic study of Ba^+ atomic properties using a relativistic all-order method. Energy levels, transition matrix elements, lifetimes, hyperfine constants, and polarizabilities are calculated. This work is motivated by the possibility to study the parity nonconservation (PNC) with a single trapped ion. Comparison of the experimental weak ...
We calculate the lifetime distribution function of an assembly of polarized atoms in two-dimensional (2D) photonic crystals (PCs) at different polarization orientations of atomic dipole moments. We reveal a switching effect of atomic spontaneous emission (SE) and find a significant change of ...
The development of atom interferometers represents a significant advance in atomic physics. They give us the ability to measure accurately interactions that shift the phase or energy of the particles in one of the two interfering paths in the interferomet...
Optical tweezers have become powerful tools for the confinement and manipulation of neutral atoms, molecules, mesoscopic biological molecules and living cells. In our experiment, a single caesium atom was prepared in a large-magnetic-gradient magneto-optical trap (MOT). It was then efficiently transferred back and forth between the MOT and a 1064 nm ...
The delayed coincidence photon counting technique, employing a picosecond tunable dye laser as an excitation source, has been used for accurate determinations of radiative lifetimes of excited states. Excitation from meta-stable states of sputtered atoms was employed. We obtained for Cu: ?(3 d 10 4 p 2 P 1/2 = 7.27(0.06) ns, ?(3 d 10 4 ...
A relativistic version of the coupled-cluster single-double (CCSD) method is developed for atoms with a single valence electron. In earlier work, a linearized version of the CCSD method (with extensions to include a dominant class of triple excitations) led to accurate predictions for energies, transition amplitudes, hyperfine constants, and other ...
A new method to measure the lifetime of the formed in the reaction exp 106 Cd+p at Ep=10 and 12 MeV is described. The nuclear lifetime is compared to the known lifetime of an atomic inner shell vacancy created in the entrance channel of the nuclear reacti...
abstract- Positron Annihilation Spectroscopy is a powerful experimental tool for probing defects in crystalline materials. The correct identification of defects with PAS requires the knowledge of accurate positron lifetimes for the various kinds of defects. That can be provided by numerical calculations in the framework of the Two-Component ...
We have measured the lifetime of the 5s5p 3P2 metastable state of strontium atoms by magneto-optically trapping the decayed atoms to the ground state, which allowed sensitive detection of the rare decay events. We found that the blackbody radiation-induced decay was the dominant decay channel for the state at T=300 K. The ...
A standard lifetime value is needed in Cl-36 for the analysis of GRID data. The lifetime values reported in the literature are not sufficiently accurate and reliable for this purpose. The lifetime of the 1.959 MeV state in Cl-36 was measured to be 68 + or...
The lifetime of two metastable levels in Fe+ has been measured by laser probing of a stored ion beam. In the dense spectrum of Fe+, the metastable levels a (6)S(5/2) and b (4)D(7/2) were selected and their lifetimes were determined to be 230 +/- 30 and 530 +/- 30 ms, respectively. The lifetimes are compared with previous theoretical ...
Source fingerprints for 18 nonmethane hydrocarbons (NMHCS) containing 2-8 carbon atoms are currently used to apportion NMHC sources by chemical mass balance (CMB) modeling approaches. The source profiles must be stable in the troposphere to obtain accurate CMB model predictions. The NMHC source apportionment compounds are susceptible to gas phase oxidation ...
We aim at demonstrating the feasibility of accurate theoretical studies of atoms and ions having complex electronic configurations, open f shell included, by combining the second quantization method in coupled tensorial form with a quasispin technique, leading to triple tensors (in orbital, spin, and quasispin spaces). The large-scale nonrelativistic and ...
The decays of the 2p J = 1/2 and J = 3/2 levels of Li-like ions and of the 2s2p {sup 1,3}P{sub 1}{sup 0} levels of Be-like ions can be used as simple-atom test beds for experimental lifetime measurements and for the development of accurate calculations of the transition rates. They have summarized and filtered the experimental data in ...
A new experiment is described which avoids the neutron problem by comparing accurately the mu exp - and mu exp + lifetimes in liquid hydrogen. In addition by comparing the lifetime of neutrons from mu capture and electrons from mu decay, uncertainties abo...
A model for predicting nickel-hydrogen battery lifetime in LEO applications has been extended to the conditions encountered in GEO orbiting satellites. The model has been found to accurately reproduce the lifetimes observed from available accelerated GEO ...
A measurement of the lifetime and capture rate of negative muons in various elements is reported. The timing system was calibrated in terms of the accurately known positive muon lifetime. The values obtained are in reasonable agreement with previous experimental data, and have a comparable accuracy. (auth)
Contents: Atomic hyperfine structure; Atomic lifetimes; Atomic frequency standards; Microwave spectroscopy; Molecular beam maser spectroscopy; Optical radio-frequency double-resonance studies of molecular excited states; Interaction between a neutral beam...
A general method for determining the branching ratio for an optical transition in neutral atom atomic beams is described. By utilizing the value of the branching ratio obtained, and the lifetime of the upper level, high precision absolute cross sections can be determined.
New methods for discovering and identifying new electronic levels of atomic uranium and measuring parameters, such as radiative lifetimes and absorption cross-sections, are described. The uranium atoms are produced within an especially designed induction-...
X-Ray and Auger transition probabilities were calculated for atoms that have been singly and multiply ionized in inner shells. The effects of relativity and configuration interaction on these rates were studied, and lifetimes of atomic inner-shell holes w...
Radiative lifetimes of levels of atoms and singly charged ions of rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) are compiled and analyzed. These data were derived by various experimental and theoretical methods. The data on radiative lifetimes of high-lying levels belonging to several Rydberg series are ...
We use two-photon resonant excitation and time-correlated single-photon counting techniques on a sample of 210Fr atoms confined and cooled in a magneto-optical trap to measure the lifetime of the 9s excited level. Direct measurement of the decay through the 7P(3/2) level at 851 nm yields a lifetime of 107.53 +/- 0.80 ns. PMID:14587813
Measurements of atomic lifetimes by the beam-foil technique and branching ratios by use of a gas-flow stabilized arc have led to an experimental determination of absolute and relative oscillator strengths of V I and V II. Some lifetimes of V III are also presented. (auth)
Measurements of atomic lifetimes by the beam-foil technique and branching ratios by use of a gas-flow stabilized arc have led to an experimental determination of absolute oscillator strengths of Ti II. Some lifetimes of Ti I, Ti III, and Ti IV are also presented. (auth)
other quantities; cold atoms have succeeded in producing the most accurate atomic clocks to date interferometers. Atomic Clocks Time is the most accurately measurable quantity in a laboratory setting sundials of 3500 BC, to the cold atom clocks developed in the last few ...
Many astrophysical and laboratory plasmas possess Maxwell-Boltzmann (MB) electron energy distributions (EEDs). Interpreting or predicting the properties of these plasmas requires accurate knowledge of atomic processes such as radiative lifetimes, electron impact excitation and de-excitation, electron impact ionization, radiative ...
The positron lifetimes of two organic superconductors, {kappa}-(ET){sub 2}Cu(NCS){sub 2} and {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br, are measured as a function of temperature across {Tc}. A drop of positron lifetime below {Tc} is observed. Positron-electron momentum densities are measured by using 2D-ACAR to search for the Fermi surface in {kappa}-(ET){sub ...
The mean life of the positive muon at rest was accurately measured in a zero magnetic fleld with a pulsed beam and found to be 2.1973 plus or minus 0.0003 mu s. (auth)
Basic atomic and molecular collision phenomena are operative at the core of an enormous range of astrophysical plasmas, including the interstellar medium (ISM), protostellar regions, stars, our Sun, and planetary atmospheres, ionospheres, & magnetospheres. Laboratory measurements of cross sections and lifetimes are needed to establish plasma ...
The spectrum of singly ionized titanium was analyzed by photographic spectral recordings of the light from a hollow cathode. Classified lines in the region 1200 A to 11000 A and term values are reported. Lifetime of the 3p 5 5p levels in neutral argon wer...
o f determining atomic excited state lifetime) with a single value of excited state lifetime in spite ... Oscillations in Beryllium - Dr. Richard W. Genberg ...
Accurate measurement of stoichiometry of GaAs provides new data which are used for calculation of the atomic weight of Ga. Using the IUPAC accepted value for the atomic weight of As (74,9216), the atomic weight of Ga based on this work is 69,737 + or - 0....
The goal of the DIRAC experiment at CERN (PS212) is to measure the ?? atom lifetime with 10% precision. Such a measurement would yield a precision of 5% on the value of the S-wave ?? scattering lengths combination |a?a|. Based on part of the collected data we present a first result on the lifetime, ?=[2.91?0.62+0.49]�10 s, and ...
The goal of the DIRAC experiment at CERN (PS212) is to measure the ?+?- atom lifetime with 10% precision. Such a measurement would yield a precision of 5% on the value of the S-wave ?? scattering lengths combination |a0 - a2|. Based on part of the collected data we present a first result on the lifetime, ? = [2.91 -0.62+0.49] � 10-15 ...
The natural radiative lifetime of some low-lying excited levels in Tm atoms have been determined from measurements of time-resolved laser-induced fluorescence in atomic beam. The levels were selectively populated by the light from a pulsed tunable dye laser pumped by an excimer laser or a Nd:YAG laser.
Although it may sound like a contradiction in terms, the electron beam ion trap (EBIT) works as an ion trap even when the electron beam is switched off. We present various experiments that exploit the ''magnetic trapping mode'' for investigations of ion confinement, charge exchange processes, atomic lifetime and ion mass ...
The DIRAC experiment at CERN has achieved a sizeable production of ?+?? atoms and has significantly improved the precision on its lifetime determination. From a sample of 21 227 atomic pairs, a 4% measurement of the S-wave ?? scattering length difference |a?a||syst?0.0073+0.0078)M?+?1 has been attained, providing an important test of ...
Of the many candidates employed for understanding the erosion of critical Extreme Ultraviolet Lithography (EUVL) components, potential energy damage remains relatively uninvestigated. Unlike the familiar kinetic energy sputtering, which is a consequence of the momentum transferred by an ion to atoms in the target, potential energy sputtering occurs when an ion rapidly collects ...
orbital and the number of H-atoms connected to the central heavy atom (see Table 1). In Figure 1, we of the van der Waals radius of the ith and the jth atoms with values taken from the CHARMM22 force field (seeHAAD: A Quick Algorithm for Accurate Prediction of Hydrogen Atoms in Protein ...
Extensions of the recently introduced ``Morse/long-range'' (MLR) potential function form allow a straightforward treatment of a molecular state for which the inverse-power long-range potential changes character with internuclear separation. Use of this function in a direct-potential-fit analysis of a combination of new fluorescence data for 7,7Li2, 6,6Li2, and 6,7Li2 with previously reported data ...
The evaluation of different surface coatings used in alkali metal atomic magnetometers is necessary for the improvement of sensitivity of these devices. A method to measure the polarization lifetime of alkali atoms in the region between substrates with different coatings was developed to determine the effectiveness of the coating at ...
Atomic Frequency Standards ... Most Make a Frequency Standard Requirements (stability only. not accuracy) plus ... accurate (1 second every 30 million years) ...
Jan 10, 2003 ... The segment discussed the need for accurate atomic clocks, how they impact our lives, and about future optical frequency atomic clocks. ...
... As atomic clocks were shown to be more accurate and stable than those based on astrometry, the SI second was redefined.[l] It now seems that an ...
An accurate analysis of aluminum alloys is required for quality control and characterization purposes. The two analytical techniques atomic absorption spectroscopy and inductively coupled plasma atomic emission spectroscopy are used for the the determinat...
4 days ago ... Atomic clocks are the most accurate time keepers in the world. An atomic clock is a precision clock that depends for its operation on an ...
... Page 4. Approved For Public Release, Distribution Unlimited Atomic Clocks � Time: most accurately measured physical quantity ...
the atomic structure of highly stripped heavy ions, and their modes ... Metastable State Lifetimes of Highly Stripped Ions. By ...
quantum numbers 100 or higher. The lifetime formula by Omidvar gives an ... genlike atom in a quantum state speci- fied by the quantum number n behaves ...
... Abstract : The radiative lifetimes of some doublet P(3/2) states of metal atomic ions have been measured in a flowing helium afterglow by using the ...
New absolute atomic transition probability measurements are reported for 12 transitions in Cr II and
... theory and experiments of the gaseous electronics por- tion of the proposed Balmer-X atomic hydrogen laser ... lifetime. ... taneous-emission decays. ...
... then experience optical gain via stimulated emission. ... monitoring the fluorescence of Balmer a transitions ... an H atom fluorescence lifetime near 3 ...
... described in (1) and (3). Local Ion Layer Simulation. ... ions (whose chemical lifetimes are much longer at night due to the lower ionization densities). ...
... be of sufficient purity, since defects (alterations from the perfect periodic lattice of Si and C atoms) can trap mobile charge carriers (electrons or holes ...
... of atoms of each type of gamma emitter is ... number, K, of gamna rays accompanying decay to the ... Since this isotope decays with mean lifetime, Ti ...
determine the stability and thermal properties of a solid ... We will also measure the characteristic lifetimes and diffusion of atomic species in these ... NMR measurements of the relaxation times T2 and T1 that are directly related to ...
... have contained up to 11.5 atomic percent neodymium activator ions ... In addition to absorption and fluorescence measurements, lifetime studies are ...
Jun 13, 2001 ... It is expected that these mesas can be used for fabricating SiC and GaN devices with major improvements in performance and lifetime. ...
... the decay of the localized vibration ImHFI - F(1 ... occupation phonon numbers of vibrations in semi ... and Technology "Surface Atomic Structures", grant ...
... Abstract : A multi-channel time interval recording system used for radiative lifetime ... with the aid of a crystal time standard, a scaler, fast inhibit logic ...
macroscopic Riemannian curvature tensor. 1". This condition may be observed as frequency shifts of Rydberg atoms with high lifetimes near ...
Since their first experimental observation, ultralong-range Rydberg molecules consisting of a highly excited Rydberg atom and a ground state atom [1, 2] have attracted the interest in the field of ultracold chemistry [3, 4]. Especially the intriguing properties such as size, polarizability and type of binding they inherit from the Rydberg ...
Atomic Physics PHYS 210- Spring 2006 Atomic physics is a sub-field of physics that focuses on properties of individual atoms and systems with relatively weak interactions between atoms. Since atoms can be accurately described using only basic quantum mechanics they can be ...
The positron annihilation lifetimes of He-ion-irradiated Fe samples were measured by a pulsed positron beam technique. The relative thickness of the surface oxidation layer was measured by Auger microprobe measurements. Unirradiated samples with different surface oxidation layer thicknesses had very similar second lifetime component intensities, indicating ...
Using collinear fast beam cw dye laser modulation spectroscopy, accurate lifetimes in Th II have been measured. Together with known branching ratios, these lifetimes have allowed the determination of absolute oscillator strengths for Th II. This element is of astrophysical interest as a chronometer for stellar and galaxy evolution, ...
Zylon composite fiber strands under tension demonstrate decreasing lifetime with increased load. The creep rupture experiment aims to accurately measure this load-lifetime relationship. The experiment found that a log-log plot of load compared to lifetime demonstrates an overall trend that suggests an additional ...
NSDL National Science Digital Library
Momentum-space two-body perturbation wave functions are applied to an accurate evaluation of the nonadditive three-body interaction among well-separated three hydrogen atoms.
By the use of the local-scaling density-functional method, simple yet accurate isotropic Compton profiles are variationally determined for the helium atom within the Hartree-Fock framework.
A method for accurately approximating T-matrix elements in atom-diatom collisions is presented. Calculations are given for hydrogen helium collisions. (AIP)
The main goal of this paper is to show how BEES technique can be used as an accurate tool for determining reliable hot-electron lifetimes in metals. This is achieved by presenting a first-principles transport theory of BEES, except for the metal lifetimes, that are treated as parameters to be fitted to the BEES current. We have ...
A pulse photolysis method has been used to study the absorption spectra and kinetics of deactivation of triplet molecules of tetra-4-tert-butylphthalocyanine, meso-tetraphenylporphine, and their metal derivatives in degassed liquid toluene solutions. The position of the triplet-triplet absorption maximum is only very slightly dependent on the nature of the central atom. The ...
PARCS will make even more accurate atomic time available to everyone, ... PARCS is being developed by the Jet Propulsion Laboratory with principal ...
