Formulation and implementation of direct algorithm for the symmetry-adapted cluster and symmetry-adapted cluster-configuration interaction method.

摘要: We present a new computational algorithm, called direct for the symmetry-adapted cluster (SAC) and SAC–configuration interaction (SAC-CI) methodology ground, excited, ionized, electron-attached states. The perturbation-selection technique molecular orbital index based sigma-vector algorithm were combined efficiently with use of sparse nature matrices involved. formal cost was reduced to O(N2×M) system N-active orbitals M-selected excitation operators. SAC-CI program has been applied several small molecules free-base porphin shown be more efficient than conventional nondirect almost all cases. Particularly, acceleration significant large dimensional computations. achieved an improvement in both accuracy efficiency. It would open possibility SAC/SAC-CI studying various kinds e...