CALCULATION OF MOLECULAR MAGNETIC-PROPERTIES WITHIN THE LANDAU GAUGE IN HYDROGEN-FLUORIDE, AMMONIA, AND METHANE MOLECULES

The magnetic susceptibility and the nuclear magnetic shielding tensors of HF, NH3, and CH4 molecules in the presence of a spatially uniform time-independent magnetic field have been calculated within the Landau gauge for the vector potential. The random-phase approximation has been used, adopting flexible Gaussian basis sets of large size. Magnetic susceptibilities are quite harder to evaluate accurately in the Landau gauge than in Coulomb gauge. Calculated nuclear magnetic shieldings are close to the Hartree-Fock limit. Sum rules for charge conservation and origin independence of magnetic susceptibility and nuclear magnetic shieldings are fairly well satisfied by basis sets of extended size.