Approximate Relativistic calculations within the one-center approximation for the series CH4 TO PbH4

Using one-component relativistic theory combined with an Xαβ local exchange, we have carried out calculations for the series CH₄ to PbH₄ within the spherically symmetric one-center expansion approximation. Bond lenghts, breathing force constant, ionization potentials and spin-orbit splitting of the filled valence p shell thus obtained, are found to be in excellent agreement with Dirac-Hartre-Fock results.