Ab initio interatomic potentials and transport properties of alkali metal (M = Rb, Cs) - rare gas (Rg = He, Ne, Ar, Kr, Xe) media

Medvedev, A.; Meshkov, V.; Stolyarov, A.; Heaven, M.C.

Авторы: Medvedev Alexander, Meshkov Vladimir, Stolyarov Andrey, Heaven Michael C.
Журнал: Physical Chemistry Chemical Physics
Том: 20
Год издания: 2018
Издательство: Royal Society of Chemistry
Местоположение издательства: United Kingdom
Первая страница: 25974
Последняя страница: 25982
DOI: 10.1039/C8CP04397C
Аннотация: We performed a first principle systematic calculation on the adiabatic potential energy curves (PECs) of alkali metal (M = Rb, Cs) - rare gas (Rg = He, Ne, Ar, Kr, Xe) van der Waals molecules over a wide range of interatomic distance $R$. All electron basis sets of triple and quadruple zeta valence quality were used for the He, Ne, Ar and Kr atoms. Scalar relativistic effects were taken into account for the heavy Rb, Cs and Xe atoms by means of Dirac-Fock effective core potentials. The correlated ground state energies have been obtained within the framework of the spin unrestricted open-shell coupled cluster method, with perturbative treatment of triple excitations. The electronic energies were corrected for the basis set superposition error (BSSE) via the counterpoise method. Energies were extrapolated to the complete basis set (CBS) limit using a two-point scheme. The energy convergence towards the CBS limit was monitored by the saturation of the dummy atom basis set that included bond functions centered at the midpoint of the interatomic distance. The ab initio point-wise PEC was followed to small $R$ to the point where the energy was 0.5 Hartree above the dissociation limit. A Morse - long range (MLR, $U^MRg(R)$) potential possessing the correct asymptotic behavior at $R\to \infty$ was fitted to the single point energies. The resulting set of fully analytical MLR potentials were then used to evaluate classical collision integrals over a wide range of collision energies. By this means, diffusion coefficients ($D^MRg(T)$) were predicted as functions of the translation temperature $T\leq 3000$ K. The reliability of the present $U^MRg(R)$ and $D^MRg(T)$ functions were accessed through a comparison with previous theoretical and experimental results.
Добавил в систему: Столяров Андрей Владиславович

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Ab initio interatomic potentials and transport properties of alkali metal (M = Rb, Cs) - rare gas (Rg = He, Ne, Ar, Kr, Xe) mediaстатья Исследовательская статья

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