On the molecular electric quadrupole moment and the electric-field-gradient-induced birefringence of CO2 and CS2

An ab initio investigation of the quadrupole moment, the polarizability ani sotropy and the temperature-independent term entering the electric-field-gr adient-induced birefringence (EFGB) of CO2 and CS2 is presented. For the la tter property, the results allow us to analyze numerically the differences between two semiclassical theories of the EFGB for nonpolar systems. Accura te electric quadrupole moments are obtained from the combined use of couple d cluster methods and diffusely augmented correlation-consistent basis sets . For CO2, our best ab initio estimate of Theta(0) = (-14.29 +/- 0.09) X 10 (-40) Cm-2 is in excellent agreement with the two most recent experimentall y deduced results (-14.3 +/- 0.6)X 10-40 Cm-2 and (-14.27 +/- 0.61) X 10(-4 0) Cm-2. (C) 2000 Elsevier Science B.V. All rights reserved.