FACTORIZATION OF THE MATRIX-ELEMENTS OF 3-ELECTRON OPERATORS USED IN CONFIGURATION-INTERACTION STUDIES OF THE ATOMIC F-SHELL

Single-electron excitations of the atomic f shell are usually taken in to account in analyses of lanthanide and actinide spectra by including six three-electron scalar operators ti in the Hamiltonian, Their matr ix elements have been factorized for all f(N) by using the Wigner-Ecka rt theorem applied to Racah's groups SO(7) and G(2). The two component parts, namely a reduced matrix element in G(2) and an isoscalar facto r, are tabulated, This provides a compact representation of the values of the matrix elements and also enables unusual selection rules and p roportionalities to be exposed. (C) 1996 Academic Press, Inc.