Theoretical investigation of equilibrium structure, harmonic force field and vibrational spectra of borane diammine: effects of basis set and electron correlation

Abstract

The equilibrium structure, harmonic force field and vibrational spectra of borane diammine, BH(NH 2) 2, have been investigated with the aid of SCF, MP2 and QCISD methods, applying a basis set of DZ + P quality. The effects of a larger basis set (TZ + 2P) including diffuse and higher order polarization functions on the computed molecular structure, harmonic force constants, vibrational frequencies and infrared band intensities of BH(NH 2) 2 have also been studied at the SCF as well as the MP2 level of approximation. The vibrational analysis of BH(NH 2) 2 and several of its isotopomers has been carried out using the GF matrix method. The predicted frequency for NH 2 wagging is very sensitive to the method of calculation; however, the predicted band intensity remains nearly unaffected.