Theoretical calculations of excited state absorption

Excitation energies and transition dipole moments between excited electroni c states have been calculated using various theoretical methods to investig ate the ability to describe excited state absorption. Quadratic response th eory is used in combination with self-consistent field, multi-configuration al self-consistent field, and coupled-cluster electronic structure methods. The results of these different methods are compared. The set of molecules considered includes lithium hydride, carbon monoxide, formaldehyde, formami de, and sym-tetrazine. For some of the molecules results are also compared with the method of applying linear response theory to an excited state wave function separately optimized by means of the multi-configurational self-co nsistent field method.