Many-body interactions and the electric response of hydrogen-bonded molecular chains

Quantitative analysis of the impact of intermolecular interactions on the nonlinear electric response of hydrogen-bonded molecular chains has been performed. In particular, the theoretical description of cooperative effects (nonadditivity) based on the many-body calculations is provided. Nonlinear optical response of H-bonded chains (linear and zigzag HF⋯(HF)n, linear H2CO⋯(H2CO)n and H3N⋯(HF)n, where n = 1-4) has also been studied. Values of the static electric dipole moment, polarizability and first-order hyperpolarizability have been calculated and analyzed at the MP2 level of theory using Dunning's correlation-consistent basis set. The site-site function counterpoise (SSFC) method has been applied in order to avoid basis set superposition error (BSSE). Particularly interesting observations have been drawn in the case of first-order hyperpolarizability.