Local unitary transformation method for large-scale two-component relativistic calculations. II. Extension to two-electron Coulomb interaction

Research output: Contribution to journalArticle

27 Citations (Scopus)


The local unitary transformation (LUT) scheme at the spin-free infinite-order Douglas-Kroll-Hess (IODKH) level [J. Seino and H. Nakai, J. Chem. Phys. 136, 244102 (2012)], which is based on the locality of relativistic effects, has been extended to a four-component Dirac-Coulomb Hamiltonian. In the previous study, the LUT scheme was applied only to a one-particle IODKH Hamiltonian with non-relativistic two-electron Coulomb interaction, termed IODKHC. The current study extends the LUT scheme to a two-particle IODKH Hamiltonian as well as one-particle one, termed IODKHIODKH, which has been a real bottleneck in numerical calculation. The LUT scheme with the IODKHIODKH Hamiltonian was numerically assessed in the diatomic molecules HX and X 2 and hydrogen halide molecules, (HX) n (X F, Cl, Br, and I). The total Hartree-Fock energies calculated by the LUT method agree well with conventional IODKHIODKH results. The computational cost of the LUT method is reduced drastically compared with that of the conventional method. In addition, the LUT method achieves linear-scaling with respect to the system size and a small prefactor.

Original languageEnglish
Article number144101
JournalJournal of Chemical Physics
Issue number14
Publication statusPublished - 2012 Oct 14


ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this