Optical rotation studied by density-functional and coupled-cluster methods

We describe the implementation of a gauge-origin independent, time-dependent linear-response formalism for the calculation of optical rotation using London atomic orbitals and density-functional theory. We test the accuracy of density-functional methods for studying optical rotation on difficult systems by modeling the optical rotation as a function of the dihedral angle. We also report the first linear response coupled-cluster singles-and-doubles results of optical rotation. The B3LYP functional gives reliable results for the optical rotation, even for molecules with nearly degenerate excited electronic states of opposite polarization.