Relativistic coupled cluster calculations using hybrid basis functions

Abstract

In this paper we present a new method of generating a relativistic basis set for atomic Dirac-Fock (DF) orbitals. Here, all the occupied and a few low-lying unoccupied DF orbital wavefunctions of atoms obtained from the finite basis set expansion approach are replaced by orbital wavefunctions obtained from numerical solutions. We compare this with the Gaussian basis set generation by employing orbitals obtained from both the approaches in a coupled cluster method and computing the ionization potential and oscillator strengths for Mg+ and Ca+ using the above two different bases. The new method is found to be more appropriate for high-precision calculations.