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1.
E. A. Andreev 《Theoretical chemistry accounts》1973,30(2):191-196
Different cases of the exchange interaction in the system (A+e+C+) are considered and corresponding expressions for this interaction are obtained. A suitable representation for the electron atom interaction is also discussed. 相似文献
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Developed formulas for the exchange interaction energy between two neutral one-active electron atoms interacting at large distances R are presented in terms of known basic integrals obtained from an asymptotic method for the alkali dimers M2 dissociating to M(ns) + M(ns), M(n′l) + M(n′l), l = 0, …, 3 and M (np) + M(np). Detailed illustrative numerical results are displayed for the molecular states of Na2 dissociating to the limit Na(3s) + Na(3p). Comparisons with very accurate ab initio results as well as with some available experimental data show that accurate potential energy curves for these excited states may be obtained in a very large range of internuclear distances by connecting ab initio curves for small and intermediate values of R with long-range curves obtained as the sum of usual multipolar Coulombic energy and asymptotic exchange energy. 相似文献
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W. Koos 《International journal of quantum chemistry》1967,1(2):169-186
Long-range interaction energy between two hydrogen atoms has been computed in the second order of the perturbation theory. All states of the system arising when one of the atoms is in the 1s and the other in the 2s or 2p state have been considered. The energy represented by a series expansion in inverse powers of the internuclear distance, R, has been computed up to the terms in R?8. The results are believed to give reliable interaction energies for R > 15 a.u. Accurate interaction energy for two ground-state hydrogen atoms has also been obtained up to the terms in R?10. Results for the B′ 1∑ state are employed to discuss the experimental ground-state dissociation energy of H2, D2, and HD. For H2 all values of the dissociation energy obtained from various experimental absorption limits, by using the computed potential energy curve to separate off the effect of rotation, are shown to be satisfactorily consistent. The resulting total energy of H2 is, however, higher than the most accurate theoretical value. 相似文献
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Accurate values for the coefficients of the R?6, R?8 and R?10 in the series representation of the dispersion interaction between two helium atoms at distance R are obtained by a simple variation method. 相似文献
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Jozef Noga Miroslav Urban Vladimír Kellö Ivan Hubač 《Theoretical chemistry accounts》1981,59(3):309-317
The efficiency of the MB-RSPT in the calculations of the correlation contributions to the interaction energies was investigated, using He2 as a model Van der Waals system. The attention has been focused on the convergency of the perturbation expansion in the calculations of the interaction energy and on the analysis of the fourth-order terms of MB-RSPT. The rôle of the renormalization term in the correct long-range behaviour of the interaction potential has been emphasized. 相似文献
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A. V. Levanov O. Ya. Isaikina E. E. Antipenko V. V. Lunin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(9):1488-1492
A mechanism and kinetic model for the synthesis of peroxide radical condensate via the low-temperature interaction of hydrogen atoms with O2 molecules is proposed. The main components of the reaction, hydrogen tetroxide H2O4 and hydrogen peroxide H2O2, are formed in a low-temperature liquid layer formed near the cold surface during synthesis. Molecules of H2O4 and H2O2 are stabilized by transitioning to the solid phase. The dependences of the \(N_{O_2 } /N_{H_2 O_2 }\) ratio on the ratio of concentrations of H and O2 in the gas phase, calculated on the basis of the model, are consistent with the experimental data. 相似文献
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A. I. Kitaygorodsky 《Tetrahedron》1961,14(3-4):230-236
A universal interaction curve of non-bonded carbon and hydrogen atoms has been proposed. This curve has been successfully applied to determine numerous properties of various saturated and unsaturated hydrocarbons such as the equilibrium of molecular conformation, the strain energy of molecules, the sublimation heat of organic crystals and so on. 相似文献
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The simple model of short-range interactions described in the preceding paper has been applied to the study of the orientation dependence of the interaction between the non-bonded hydrogen atoms of two CH fragments. Calculation shows that for the same interatomic distance the interaction energy between non-bonded hydrogen atoms is strongly dependent on the relative orientation of the two bonds even for large values ofR. 相似文献
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根据气体的VanderWaals常数和两个氢原子间的VanderWaals能之理论值,计算了两个氢、氮、氧或氯原子间的VanderWaals能。 相似文献
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Conclusions The first, chemisorbed monomolecular layer of N2O is the site of the most intense reaction between gaseous atomic hydrogen and nitrous oxide adsorbed on platinum.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 507–510, March, 1979. 相似文献
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Dr. Raymond G. Jesaitis 《Theoretical chemistry accounts》1973,32(1):71-75
The directional components of the barrier to rotation in hydrazine are investigated. The repulsion of the lone pairs appears to be significant, favoring the form with perpendicular lone pairs over the syn and anti forms.[/p] 相似文献
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Boron substitution in carbon materials has been comprehensively investigated using the density functional theory method. It was found that there is a correlation between the stability of the graphene sheet, the distribution of pi electrons, the electrostatic potential, and the capability for hydrogen-atom adsorption. Boron substitution destabilizes the graphene structure, increases the density of the electron wave around the substitutional boron atoms, and lowers the electrostatic potential, thus improving the hydrogen adsorption energy on carbon. However, this improvement is only ca. 10-20% instead of a factor of 4 or 5. Our calculations also show that two substitutional boron atoms provide consistent and reliable results, but one substitutional boron results in contradictory conclusions. This is a warning to other computational chemists who work on boron substitution that the conclusion from one substitutional boron might not be reliable. 相似文献
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M. -W. Ruf A. J. Yencha H. Hotop 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1987,5(1):9-20
Using crossed beams of ground state alkali atoms A (A = Li, Na, K, Rb, Cs) and metastable He(23 S), He(21 S) atoms, we have measured the energy spectra of electrons resulting in the respective Penning ionization processes at: thermal collision energies. The data are interpreted to yield the well depthD e * of the2Σ interaction potentials as follows: He(23 S)+A:D e * (A=Li)=868(20) meV;D e * (Na)=740(25) meV;D e * (K)=591(24) meV;D e * (Rb)=546(18) meV;D e * (Cs)=533(18) meV. He(21 S)+A:D e * (Li)=330(17) meV;D e * (Na)=277(24) meV;D e * (K)=202(23) meV;D e * (Rb)=219(18) meV;D e * (Cs)=277(18) meV. The well depth for He(23 S)+A(2Σ) is always close to 80% of the well depth for Li(2s)+A(X 1Σ). The ionization cross sections for He(21 S)+A are about 3 to 4 times larger than those for He(23 S)+A. 相似文献
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W. Koos 《International journal of quantum chemistry》1975,9(1):133-142
The energy of the hydrogen molecule in the B 1Σ state, for internuclear separations 12 ≦ R ≦ 20 a.u., has been computed using an 80-term variational wave function depending explicitly on the interelectronic distance. The same type of wave function has been employed in the perturbation theory approach. Using the polarization approximation, and not expanding the interaction Hamiltonian, the first-, second- and third-order energies have been computed and higher-order corrections have been estimated. The results show that in the region under consideration E and E represent the dominant contributions to the interaction energy in the B state. 相似文献
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Irene Shim Jens Peder Dahl Helge Johansen 《International journal of quantum chemistry》1979,15(3):311-331
The interaction between two nickel atoms in the configurations (3d)8(4s)2 and (3d)9 (4s)1 has been calculated using ab initio methods (Hartree–Fock and configuration interaction). The results of the calculations compare favorably with the optical spectrum. The discrepancy between the calculated and the experimental dissociation energy is discussed, and a new estimate of the dissociation energy is given. The configuration-interaction calculations show that the interaction between the two nickel atoms is of a very complex nature. In spite of this the binding can be interpreted in a simple way. The bond is minly due to the 4sσg molecular orbital while the 3d orbitals of the two nuclei are exchange coupled. 相似文献