Calculation of the A term of magnetic circular dichroism based on time dependent-density functional theory I. Formulation and implementation

The A term of magnetic circular dishroism based on time-dependent density functional theory (TD-DFT) was discussed. The TD-DFT approach was a simple one and two potentially important contributions which include those required to ensure gauge dependence and those dependent on the derivative of the integrals over the time-dependent functional, were neglected. It was found that the A/D ratios and the relative magnitude of A term was found to be good, leading to simulate spectra that were similar in appearance to those derived from measurements. It was also observed that the A terms were found to be too small whenever comparison with experiment was possible.