Total energies and energy gradients in electron propagator theory

From the second-order self-energy of electron propagator theory, one can obtain total energies for the initial, N-electron state and the final, N ± l-electron states. Recent derivations and computational studies have demonstrated the feasibility of calculating effective first-order density matrices corresponding to the electron-binding energies. One-electron properties and energy gradients of the final states are thereby made accessible. Applications to. the ground and excited states of CaCN and to C illustrate the capabilities of this method.