Ab-initio calculation of van der waals constants (C6, C8, C10) for two-valence-electron atoms, including correlation effects
✍ Scribed by F. Maeder; W. Kutzelnigg
- Publisher
- Elsevier Science
- Year
- 1976
- Tongue
- English
- Weight
- 460 KB
- Volume
- 37
- Category
- Article
- ISSN
- 0009-2614
No coin nor oath required. For personal study only.
✦ Synopsis
The Cb-. CS-. and C'ln-coefficicnts of the asymptotic expansion of the intcrnction energy in terms of powers of I/R are calculated for the p&s of atoms He-He, Be-Be, big-hip, Ca-Ca. The method involves the direct calculation of the "natural states of the subsystem under the interaction". Three approaches arc used, (a) both the unperturbed and the perturbinp wavcfunctions are of Hartrcc-Fock type, (b) the unperturbed wavefunction is correlated, (c) both types of functions are correlated. As a typical result one gers for C, of Mp-hlg in the three approuchcs (a) 1230 au, (b) 504 au, (c) 686 au. Only the results from approach (c), in which the in:ra-atomic valcncc-shell correlation is taken Carl: of, turn out lo be satisfacrory.
How much correlation has to be included to get reliable van dcr N'auIs constants is discussed.