Electronic g Tensors in UV Complexes–A Computational Study

5 years ago

Electronic g Tensors in UV Complexes–A Computational Study

Helen M. Moylan, Joseph J W. McDouall

The theory and computation of EPR parameters from first principles has seen a great deal of development over the past two decades. In particular, various techniques for the computation of the electronic g tensor have been implemented in many quantum chemistry packages. These methods have been successfully applied to paramagnetic organic species and transition metal systems. The situation is less well-understood and established in the case of actinide-containing molecules and there is a dearth of experimental data available for validation of computations. In this study quantum chemical techniques have been used to evaluate the g tensor for UV complexes, for which experimental data are available for comparison. The g tensors were calculated using relatively simple, state-averaged complete active space self-consistent field (SA-CASSCF) calculations. This approach is shown to be capable of providing useful accuracy. Aspects of the computations that should be refined to provide a more quantitative approach are discussed. The key features of the underlying electronic structure that influence the computed g values are delineated, providing a simple physical picture of these subtle molecular properties. Gee whizz: Useful accuracy can be obtained for the g tensors of UV complexes using relatively simple and well-established quantum chemical methods. By carrying out small geometric perturbations of the molecular structures it is possible to delineate the key features of the underlying structure that influence the computed values. This allows the changes in electronic structure to be related with the changes in the g values, providing a simple physical picture of these subtle molecular properties.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201701058