Correlated calculations of molecular dynamic polarizabilities

Frequency-dependent molecular polarizabilities of several molecules N-2, CO, CO2, Cl-2, C2H2, COS, and CS2 are calculated by the equation-of-motion coupled cluster singles and doubles (EOM-CCSD) method. The EOM-CCSD CI-like, linear and quadratic methods for dynamic second-order properties are presented. The importance of electron correlation, the quadratic contribution, and orbital relaxation effects are assessed. London dispersion coefficients are calculated by numerical integration of the EOM-CCSD polarizabilities. (C) 1997 American Institute of Physics. [S0021-9606(97)01541-9].