Multipole approximation of distant pair energies in local MP2 calculations
by Hetzer, G.; Pulay, P.; Werner, H. J.
An approximation for treating the weak correlation of distant pairs in local MP2 calculations by multipole expansions is proposed. This leads to computational savings in the transformation of the two-electron integrals, which is the bottleneck in MP2 calculations. The method works well for orbital pairs that are at least 7 bohr apart. The accuracy is mainly limited by the neglect of ionic excitations in the first-order wavefunction, while the error of the multipole expansion is almost negligible.
- Journal
- Chemical Physics Letters
- Volume
- 290
- Issue
- 1-3
- Year
- 1998
- Start Page
- 143-149
- URL
- https://dx.doi.org/10.1016/s0009-2614(98)00491-6
- ISBN/ISSN
- 1873-4448; 0009-2614
- DOI
- 10.1016/s0009-2614(98)00491-6