Analytical energy gradients of the excited, ionized and electron-attached states calculated by the SAC-CI general-R method

A method of calculating analytical energy gradients of the excited, ionized and electron-attached states calculated by the symmetry-adapted-cluster configuration-interaction (SAC-CI) general-R method is formulated and implemented. This method is expected to be a powerful tool in the studies of dynamics and properties of molecules in which two- and multi-electron processes are involved. Good performance of this method is shown for the singlet and triplet excited states of BH and for the doublet ground and excited states of CH.