Full-CI calculation of imaginary frequency-dependent dipole polarizabilities of ground state LiH and the C-6 dispersion coefficients of LiH-LiH

Full-CI calculations of frequency-dependent dipole polarizabilities of grou nd state LiH have been performed in the imaginary frequency range 0-20 a.u. using an extended set of 109 Gaussian type orbitals (GTOs). A 32-points Ga uss-Legendre quadrature of the Casimir-Polder formula over imaginary freque ncies allows calculation of the dipole dispersion constants for the LiH-LiH homodimer, from which isotropic C-6 and anisotropy gamma (6) dispersion co efficients are derived for the first time. (C) 2000 Elsevier Science B.V. A ll rights reserved.