Calculations of circular intensity differences in electric-field-induced second harmonic generation

Ab initio calculations of electric-field induced second-harmonic generation for chiral molecules are presented. The calculations employ cubic response theory and take into account electric-dipole, electric-quadrupole and magnetic-dipole interactions, which result in an intensity dependence on the helicity of the light. The circular intensity difference is calculated for the chiral molecules twisted ethylene, trans-1,2-dimethylcyclopropane and methyloxirane. The calculated circular intensity differences are small – being of the order of 10−4–10−3 – but such electric-field induced second harmonic generation intensity dependencies should be experimentally detectable.