Dirac-Fock-Roothaan calculations using a relativistic reduced frozen-core approximation

Yoshihiro Watanabe, Osamu Matsuoka

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


The reduced frozen-core approximation (RFCA) that has been previously used for nonrelativistic calculations is extended to relativistic calculations. The RFCA adopts a new method for the orthogonalization of valence basis functions to core orbitals. Orthogonalization is performed using corelike basis functions consisting of fewer primitive basis functions than core orbitals. Dirac-Fock-Roothaan calculations on HI and ThO show that the relativistic RFCA can reduce computing time and closely reproduce the total and valence orbital energies and spectroscopic constants obtained by all-electron calculations.

Original languageEnglish
Pages (from-to)8182-8187
Number of pages6
JournalJournal of Chemical Physics
Issue number19
Publication statusPublished - 1998

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry


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