First-order relativistic corrections to MP2 energy from standard gradient codes: Comparison with results from density functional theory
✍ Scribed by Franke, Robert; Van W�llen, Christoph
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 291 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0192-8651
No coin nor oath required. For personal study only.
✦ Synopsis
The evaluation of the first-order scalar relativistic corrections to MP2 energy based on either direct perturbation theory or the mass᎐velocity and Darwin terms is discussed. In a basis set of Levy-Leblond spinors the one-and two-electron matrix elements of the relativistic Hamiltonian can be decomposed into a nonrelativistic part and a relativistic perturbation. Thus, a program capable of calculating nonrelativistic energy gradients can be used to calculate the cross-term between relativity and correlation. The method has been applied Ž . Ž to selected closed-shell atoms He, Be, Ne, and Ar and molecules CuH, AgH, . and AuH . The calculated equilibrium distances and harmonic frequencies were compared with results from first-order relativistic density functional calculations. It was found that the cross-term is not the origin of the nonadditivity of relativistic and correlation effects.