Ab initio HF-SCF studies of the equilibrium structures and vibrational spectra of the Be(NO3)2, Mg(NO3)2 and Ca(NO3)2 molecules

HF-SCF calculations have been performed for the Mg(NO3)2, Ca(NO3)2 and Be(NO3)2 molecules to determine their stable equilibrium structures and vibrational spectra. Bidentate and monodentate structures have been taken into account and the calculations suggest that non-planar D2d is the most stable equilibrium structure for all the species considered in the work. The infrared spectra of the D2d and D2h structures of Mg(NO3)2 have been simulated on the basis of the HF/6-31G* frequency and intensity calculations, and the 18O isotope shifts have been predicted in the stretching region of the NO3 - modes. The conclusions of the calculations have been used to assign the FT-IR spectra of molecular Cu(NO3)2. The paper includes calculations for the [BeNO3]+H2O, [MgNO3]+H2O, [CaNO3]+H2O, [AlNO3]2+H2O, [BeNO2]+H2O, [MgNO2]+H2O, [CaNO2]+H2O, and [AlNO2]2+H2O hydrated species. © 1994.