Accurate Binding Energies Research Articles

The effect of oxygen on the electrical properties of silicon

Gaussian-2 (G2) theory for third-row non-transition elements is used to calculate energies of germanium clusters, Gen (n = 2−5). The G2 energies are used to derive accurate binding energies for the clusters. The results for Ge2 and Ge3 are in agreement with experiment while there is some disagreement for Ge4 and Ge5. The binding energies are also calculated using the B3LYP density functional method with the 6–311 + G(3df,2p) basis set and compared with the G2 results and experiment.

Self-Consistent-Field Theory for One-Positron Many-Electron Systems

A theory for the structure of one-positron many-electron atoms and molecules in bound states is presented. The purpose of the theory is to permit the accurate calculation of positron lifetimes, angular correlation for two-photon annihilation, and accurate positron binding energies, but not necessarily quantities which depend upon purely electronic correlation. We therefore use a modified orbital approximation for the electrons, the modification consisting of the introduction of explicit electron-positron correlation into each electronic orbital. The kinetic energies of the electrons and positron are treated on the same footing, and the Born-Oppenheimer approximation is applied to the nuclei. No spin-dependent or relativistic terms are included in the Hamiltonian. In this paper we treat only those systems for which the electrons constitute a closed shell, and we do not consider the spatial symmetry of the atom or molecule.

Dissociation Energy and Vibrational Terms of Ground-State (X 1Σg+) Hydrogen

In an attempt to elucidate the discrepancy between the theoretical and experimental dissociation energies of H2, accurate binding energies and term differences have been computed for the 15 vibrational levels using the Kolos and Wolniewicz clamped-nuclei potential with its various corrections. The results suggest possible interpretations of the discrepancy. In one of these an extrapolation method is introduced which combines experimental term differences with computed binding energies for the uppermost levels to yield the dissociation energy; this result is in accord with the experimental value of Herzberg and Monfils. The effect of uncertainties in the values of the natural constants is considered. Apparent inconsistencies between previously computed vibrational energies are explained.

Polarized wave functions for a few-body model nucleus

An approximation scheme for the wave function of a few-body system is developed, in which intrinsic polarization is introduced in a natural way. The polarized wave function is tested with model three- and four-body nuclei, and it is found that two different polarizations are nearly degenerate. The resulting resonant wave function yields accurate binding energies. Furthermore, the accuracy of the spatial density is checked by means of an error-estimating principle. The result is that the advantages of simplicity and generality of the polarized wave function are coupled with very good simulation of the correct wave function.

Das KLL-Auger-Spektrum f�r 10?Z?36

The configuration interaction, applied very recently byAsaad to the calculations ofKLL-Auger spectra, could remove the large discrepancies which existed for lowZ between experimental and theoretical relative group intensities I(KL1L2,3)/I(KL1L1) and I(KL2,3L2,3)/I(KL1L1).Asaad's calculations, however, were based on binding energies E(L1) and energies of the Coulomb and spin-orbit interaction, which were not very accurate. In the present calculations use has been made of more accurate binding energies E(L1) and Coulomb and spin-orbit interaction energies. It is shown that the absolute error in the results of the new calculations is less than 10%. From this it follows that the remaining discrepancies between theoretical and experimental values of the group intensities for 10≦Z<25 may be solely attributed to the inadequacy of the calculated transition probabilities. This calls for calculations of transition amplitudes of the KLL-process with more accurate wave functions for Z<25, in particular for Z=10.

Atomic level energies in hafnium

>The photoelectron method for obtaining electron binding energies is described. The method was applied to the L/sub I/, L/sub II/, and L/sub III/ levels in hafnium. The Hf K alpha /sub 1/ and Hf K alpha /su b 2/ x-ray emission lines were measured with a crystal spectrometer. The electron binding energies of the K to O/sub III/ shells in hafnium were obtained from photoelectron and x-ray emission data. A type of Moseley diagram is described and is demonstrated for the K and L levels in the Z region 57 to 75. From these diagrams accurate binding energies for the element Pm (Z = 81) were obtained by interpolation. (auth)