Radial moments of the electron density: Gas phase results and the effects of solvation.

The radial moments of the electron density, 〈r[sup n]〉, have been calculated for N[sub 2] and H[sub 2]O at the quadratic configuration interaction (with singles and doubles) levels of theory by use of a variety of basis sets. An optimal basis set was chosen from the first set of calculations and then used with several conventional ab initio and density functional methods to compute the moments for a representative set of molecules: N[sub 2], CO, CH[sub 4], NH[sub 3], H[sub 2]O, HF, SiH[sub 4], PH[sub 3], H[sub 2]S, HCl, CH[sub 3]OH, and CH[sub 3]SH. The effects of solvation on the radial moments were also studied using the Onsager model and an extension of the Tomasi polarized continuum model. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]