Journal of Chemical Physics, Vol.109, No.21, 9219-9236, 1998
Derivation of coupled cluster excited states response functions and multiphoton transition moments between two excited states as derivatives of variational functionals
Based on an analysis of the second residues of the coupled cluster ground state response functions, general expressions are derived for multiphoton transition moments between two excited states and for excited states response functions. The second residues are rewritten as derivatives of variational functionals and computational efficient expressions are obtained in accordance with the 2n+1 and 2n+2 rules. For the excited state response functions secular divergent terms are removed by reformulating the expressions that are identified from the second residues of the ground state response functions as derivatives of an excited state quasienergy Lagrangian. Explicit expressions are given for coupled cluster one-, two-and three-photon transition moments between two excited states and for excited states first-order properties and linear and quadratic response functions,
Keywords:FULL CONFIGURATION-INTERACTION, POTENTIAL-ENERGY SURFACES;EXCITATION-ENERGIES, APPROXIMATION, EQUATION, MODEL, CC3;HYPERPOLARIZABILITIES, SINGLES, H2O