A simple scheme for calculating approximate transition moments within the equation of motion expectation value formalism

A simple scheme for calculating approximate transition moments within the framework of the equation of motion coupled cluster method is proposed. It relies on a matrix inversion technique to calculate the excited state left eigenvectors and requires no additional cost over that of the excitation energy calculation. The new approximation gives almost identical UV-Vis spectra to that obtained using the standard equation of motion coupled cluster method with single and double excitations for molecules in a standard test set.