Calculation of reduced coefficients and matrix elements in jj-coupling

A program RCFP will be presented for calculating standard quantities in the decomposition of many-electron matrix elements in atomic structure theory. The list of quantities which are supported by the present program includes the coefficients of fractional parentage, the reduced coefficients of frac tional parentage, the reduced matrix elements of the unit operator Tk as we ll as the completely reduced matrix elements of the operator W-kjkq in jj-c oupling. These quantities are now available for all subshells (nj) with j l ess than or equal to 9/2 including partially filled 9/2-shells. Our program is based on a recently developed new approach on the spin-angular integrat ion which combines second quantization and quasispin methods with the theor y of angular momentum in order to obtain a more efficient evaluation of man y-electron matrix elements. An underlying Fortran 90/95 module can directly be used also in (other) atomic structure codes to accelerate the computati on for open-shell atoms and ions. (C) 2001 Elsevier Science B.V. All rights reserved.