CALCULATIONS OF CIRCULAR INTENSITY DIFFERENCES IN ELECTRIC-FIELD-INDUCED 2ND-HARMONIC GENERATION

Ab initio calculations of electric-field induced second-harmonic gener ation for chiral molecules are presented. The calculations employ cubi c response theory and take into account electric-dipole, electric-quad rupole and magnetic-dipole interactions, which result in an intensity dependence on the helicity of the light. The circular intensity differ ence is calculated for the chiral molecules twisted ethylene, trans-1, 2-dimethylcyclopropane and methyloxirane. The calculated circular inte nsity differences are small - being of the order of 10(-4)-10(-3) - bu t such electric-field induced second harmonic generation intensity dep endencies should be experimentally detectable. (C) 1998 Elsevier Scien ce B.V. All rights reserved.