A program for the complete expansion of jj-coupled symmetry functions into Slater determinants Original Research Article

Different applications of atomic structure theory favour different representations of the many-electron wave function. For an estimate of energy levels it is appropriate to start from symmetry adapted functions which keep the size of the Hamiltonian matrix to be diagonalized small. In the calculation of transition properties, on the other hand, the electron rearrangement during an atomic excitation or decay process can be effectively treated, if the wave functions are represented as linear combination of determinants. The relaxation of the electron density is naturally obtained in self-consistent-field calculations and is expressed in terms of the one-electron orbital functions, which are not quite orthogonal in the initial and final states of a transition. We provide a module to expand the symmetry adapted configuration and/or atomic states in the framework of the Oxford atomic structure program GRASP [F. A. Parpia and I. P. Grant, 1990] into a basis of Slater determinants which will be appropriate for forthcoming applications of the atomic multiconfiguration Dirac-Fock model.