MOLECULAR QUADRUPOLE-MOMENTS, 2ND MOMENTS, AND DIAMAGNETIC SUSCEPTIBILITIES EVALUATED USING THE GENERALIZED GRADIENT APPROXIMATION IN THE FRAMEWORK OF GAUSSIAN DENSITY-FUNCTIONAL METHOD

A series of monoelectronic properties, i.e., molecular dipole and quad rupole moments, diamagnetic susceptibility and second moments of a num ber of organic and inorganic systems (CO2, OCS, CS2, C2H2, HCN, SO2, C H3CN, C2H6, C6H5F, C5H5N, C4H4N2, and C2H2N4) have been determined by using the linear combination of Gaussian-type orbitals-density functio nal method employing both local spin density (LSD) and nonlocal spin d ensity (NLSD) approximations and triple zeta quality basis sets. The p ossible influence of an increase of radial grid points on the calculat ed properties has been also examined. Results show a general good agre ement between all calculated monoelectronic properties and the availab le experimental counterparts even at local level and with a fine grid employing 32 radial grid points. In particular for the considered mole cules the average error, at nonlocal level, with respect to the experi ment is about 0.4x10(-26) e.s.u. cm(2) for quadrupole moments, 2.0x10( -16) cm(2) for [r(2)] and 5.6x10(-6) ergs/G(2) mol for diamagnetic sus ceptibility, that is in the range of the experimental error. (C) 1996 American Institute of Physics.