THEORETICAL MOLECULAR DIPOLE-MOMENT DERIVATIVES IN SOLID HCN

A Hartree-Fock based self-consistent crystal field method is employed to calculate molecular dipole moment derivatives of HCN in the solid. Qualitative agreement with experiment is obtained for the changes in the stretching normal coordinates molecular dipole moment derivatives, when going from the gas phase to the solid. The molecular polarizabilities are calculated. The latter are translated into the high-frequency contributions to the dielectric constants. Qualitative agreement with experiment is again obtained. Intra-molecular geometry optimization is performed and an elongation of the C-H bond by 0.01 angstrom is obtained. The lattice energy is decomposed into purely electrostatic, Pauli repulsion and dispersion interaction contributions.