Configuration interaction calculation of electronic g tensors in transition metal complexes

An algorithm for the calculation of electronic g tensors from configuration interaction (Cl) wave functions and its implementation for any ground-state spin S is described. The algorithm can be used together with either single- or multireference CI wave functions but assumes a spatia)ly nondegenerate ground state. A one-electron approximation to the spin-orbit coupling (SOC) operator is used. Presently the implementation uses the INDO/S model of Zerner and coworkers. Results are presented for a representative collection of Cu(II) complexes with N-, O-, and S-containing ligands. The calculations reproduce the trends in the experimental data well and show no systematic errors. For the test set the g values are reproduced with a standard deviation of 0.021. The method has therefore a good cost-performance ratio and is expected to be helpful in chemical and biochemical applications. Further improvements are feasible and necessary and are briefly discussed. (C) 2001 John Wiley & Sons, Inc.