Configuration interaction calculation of electronic<i>g</i>tensors in transition metal complexes*

An algorithm for the calculation of electronic g tensors from configuration interaction (CI) 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 spatially 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. © 2001 John Wiley &amp; Sons, Inc. Int J Quant Chem 83: 104–114, 2001