Gauge-origin independent magneto-optical activity within coupled cluster response theory

A gauge-origin invariant formulation of the frequency-dependent Verdet cons tant V(omega) of magneto-optical rotation and of the Faraday B term of magn etic circular dichroism for coupled-cluster wave functions is derived withi n the framework of variational response theory. Working expressions suitabl e for implementation in ab initio program packages are presented. These exp ressions have a structure similar to that of the expressions for the first hyperpolarizability and the two-photon transition moment, respectively, for the Verdet constant and the B term. The approach is general and can easily be extended to other similar frequency-dependent properties as well as to other wavefunction models. Pilot results at the CCSD level are presented fo r V(omega) of HF and H-2. (C) 2000 American Institute of Physics. [S0021-96 06(00)30233-1].