2ND-ORDER MULTICONFIGURATIONAL DIRAC-FOCK SELF-CONSISTENT-FIELD AND MULTIREFERENCE CONFIGURATION-INTERACTION CALCULATIONS ON BERYLLIUM AND BERYLLIUM-LIKE NE6+

A quadratically convergent Newton-Raphson algorithm for relativistic m ulticonfigurational Dirac-Fock self-consistent field calculations is d eveloped and implemented with analytic basis sets of Gaussian spinors. A procedure to perform second-order energy optimization for a general class of multiconfigurational wavefunctions constructed from one-part icle Dirac spinors is described. We report the results of relativistic multiconfigurational Dirac-Fock self-consistent field calculations on beryllium and beryllium-like neon, followed by multireference configu ration interaction with single and double excitations out of the multi configurational Dirac-Fock wavefunctions. (C) 1997 Elsevier Science B. V.