Response properties of Furan homologues by time-dependent density functional theory

The electronic excitations and frequency-dependent electronic second hyperpolarizability gamma (-omega; omega, omega, -omega)) of the five-ring heterocycles furan, thiophene, selenophene, and tellurophene have been reinvestigated using time-dependent density functional theory. Increased hyperpolarization for molecular dimer species suggests that intermolecular interactions may provide a simple explanation for the large deviations between recent ab initio calculations and experimental condensed-phase data.