GRECP/5e-MRD-CI calculation of the electronic structure of PbH

Authors: T.A. Isaev, N.S. Mosyagin, A.V. Titov, A.B. Alekseyev, R.J. Buenker
Comments: 6 pages, submitted to Int.J.Quatn.Chem

     The correlation calculation of the electronic structure of PbH is carried out with the
     Generalized Relativistic Effective Core Potential (GRECP) and MultiReference single-
     and Double-excitation Configuration Interaction (MRD-CI) methods. The 22-electron
     GRECP for Pb is used and the outer core 5s, 5p and 5d pseudospinors are frozen
     using the level-shift technique, so only five external electrons of PbH are correlated. A
     new configuration selection scheme with respect to the relativistic multireference states
     is employed in the framework of the MRD-CI method. The [6,4,3,2] correlation
     spin-orbit basis set is optimized in the coupled cluster calculations on the Pb atom
     using a recently proposed procedure, in which functions in the spin-orbital basis set are
     generated from calculations of different ionic states of the Pb atom and those functions
     are considered optimal which provide the stationary point for some energy functional.
     Spectroscopic constants for the two lowest-lying electronic states of PbH
     ($^2\Pi_{1/2}, ^2\Pi_{3/2}$) are found to be in good agreement with the
     experimental data.

Paper: PS, PDF or other formats.