High pressure study on structural and vibrational properties of NH < inf > 3 < /inf > BH < inf > 3 < /inf >

Abstract

The structural and vibrational properties of potential hydrogen storage compound NH3BH3 have been studied through density functional theory at ambient as well as high pressures upto 10 GPa. The calculated lattice parameters at ambient pressure are in good agreement with experiments. The compressibility of NH3BH3 along the crystallographic a-axis is almost constant when compared to b- and c-axes, which is an indication of anisotropic compressibility. The zone center vibrational frequencies of NH3BH3 at ambient and 10 GPa pressures are calculated. The A2 and B1 symmetry modes are independent of pressure, whereas the A1 symmetry modes increases and B 2 symmetry modes decreases with pressure.