A comparative study of the structural, electronic, and vibrational properties of NH₃BH₃ and LiNH₂BH₃: Theory and experiment

Herein, we systematically investigate the structural, electronic, and vibrational properties of ammonia borane (NH₃BH₃, AB) and lithium amidoborane (LiNH₂BH₃ LAB) through both density functional calculations and experiments. AB and LAB samples are generated and their vibrational spectra are obtained by using Fourier transformed infrared spectroscopy (FTIR). The measured vibrational spectra are in good agreement with the calculated ones. Our calculations show that the Li-related vibration modes are primarily found in the low-frequency region (< 1000 cm^-1), and that the intermolecular interactions significantly influence the vibrational spectra. Electronic structure calculations provide insights into the differences between the binding natures of AB and LAB and their influence on the vibrational properties of these compounds.