Parallel spin-orbit coupled configuration interaction

A parallel spin-orbit configuration interaction (SOCI) code has been develo ped. This code, named P-SOCI, is an extension of an existing sequential SOC I program and permits solution to heavy-element systems requiring both expl icit spin-orbit (SO) effects and significant electron correlation. The rela tivistic procedure adopted here is an ab initio conventional configuration interaction (CI) method that constructs a Hamiltonian matrix in a double-gr oup-adapted basis. P-SOCI enables solutions to problems far Larger than pos sible with the original code by exploiting the resources of large massively parallel processing computers (MPP). This increase in capability permits n ot only the continued inclusion of explicit spin-orbit effects but now also a significant amount of non-dynamic and dynamic correlation as is necessar y for a good description of heavy-element systems. (C) 2000 Elsevier Scienc e B.V. All rights reserved.