Second-order shakeup terms in electron propagator calculations on F-2 and H2O2

摘要

A new approximation of the electron propagator includes second-order terms in the superoperator Hamiltonian matrix that are not present in the nondiagonal, renormalized method (NR2) of J. Chem. Phys. 108, 1008 (1998). These terms are not difficult to calculate and resemble expressions obtained with various propagator and coupled-cluster formalisms. Their inclusion produces larger, more accurate vertical ionization energies of F-2 and H2O2. Cancellations between the second-order terms considered here and the first-order terms present in the NR2 method reduce the importance of shakeup operators in describing the first few cationic states of these molecules. Dyson orbitals for (2)A final states of H2O2 exhibit qualitatively important mixings between canonical orbitals. (C) 1998 John Wiley & Sons, Inc. Int J Quant Chem 69: 175-182,1998. [References: 31]