LOCAL-DENSITY CALCULATIONS OF STATIC DIELECTRIC-PROPERTIES OF CH4-NCLN, N=0-4

The dipole moments, dipole polarizabilities, and static hyperpolarizab ilities of methane and the chloromethanes have been studied at the exp erimental geometry with the deMon density functional program. Using th e local density approximation and large basis sets, we computed the di pole moments of CH4-nCln, n = 0-4, at various finite fields. These fie ld-dependent dipoles were fitted to polynomials in the fields by least squares. The extracted static dielectric properties were compared wit h experimental data and found to be excellent for permanent dipole mom ents, good for polarizabilities, but only qualitative for hyperpolariz abilities.