Abstract
In this study, the Ab initio and DFT calculations of optimized geometries, energy and vibrational spectra for the Beryllium borohydride Be(BH4)(2) at different levels are achieved by Hartre - Fock (HF), perturbation theory (MP2) and density functional theory (B3LYP) methods. They utilize the 6-31G(d), 6-311G(d, p), 6-311+G(d,p) and 6-311++G(d,p) basis sets. The theoretical results showed that Beryllium borohydride with the D(2)d structure which contains two identical groups of double bridging hydrogen has the lowest energy at all levels. Consequently, this compound is considered as the most stable one and the results of IR and Raman Spectra at all levels support that. We found that both structures C-s, C-3v have the structure of D-2d kind at all levels. The values of bond lengths for these two structures are identical to the bond lengths to the structure D-2d kind which confirms this theory.