The Contribution of π Electrons to Second Harmonic Generation in Organic Molecules

The frequency-dependent hyperpolarizability for sum frequency generation is calculated within a π electron approximation for a series of unsaturated organic compounds and compared to experimental data measured in polar and nonpolar liquid media. A procedure is also suggested to investigate the influence of electrostatic intermolecular interaction on the hyperpolarizability of small clusters of molecules in relative positions corresponding to the crystal structure. © 1986, American Chemical Society. All rights reserved.