Economical treatments of relativistic effects and electron correlation in WH6

✍ Scribed by Hertwig, Roland H.; Koch, Wolfram; Yates, Brian F.

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 267 KB
• Volume: 19
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/(sici)1096-987x(19981115)19:14<1604::aid-jcc6>3.0.co;2-n

✦ Synopsis

The equilibrium geometries and relative stabilities of several structural isomers of tungsten hexahydride, WH , have been obtained at 6 different levels of quantum chemical calculations. The performance of various Ž . strategies to i include electron correlation, viz. density functional theory based Ž . approaches, MøllerrPlesset perturbation and coupled cluster theory, and to ii account for scalar relativistic effects, viz. various relativistic effective core potentials, first order perturbation theory, a quasi-relativistic treatment employing a Pauli Hamiltonian, and use of the DouglasrKroll operator, are compared to the best theoretical data available. It is shown that relativistic and electron correlation effects are most important for the high-symmetry species, that these effects give rise to opposite trends in relative energies, and that overall the relativistic effects dominate. The most efficient way to incorporate relativistic effects appears to be via the use of relativistic effective core potentials, while the correlation energies are best taken account of using a conventional Ž .