Author/Authors :
Gwaltney، نويسنده , , Steven R. and Nooijen، نويسنده , , Marcel and Bartlett، نويسنده , , Rodney J.، نويسنده ,
Abstract :
Simplified equation-of-motion coupled-cluster (EOM-CC) methods derived from matrix partitioning and perturbation approximations are presented and applied to a variety of molecules. By combining a partitioned EOM-CC method with an MBPT(2) treatment of the ground state, we obtain an iterative n5 method which gives excitation energies that normally fall within 0.2 eV of the full EOM-CCSD excitation energy. Results are shown to be superior to other simplified approaches that have been proposed.
