First principles investigations of geometric, electronic and optical properties of 5-aminotetrazole derivatives

Density functional theory (DFT) is an important computational technique to study and predict the properties of isolated molecules. It is now a leading method for electronic structure calculations in chemistry and solid state physics. In this paper, we have investigated the geometric, electronic and optical properties of six 5-aminotetrazole derivatives employing DFT. The ground state geometries were optimized at B3LYP/6-311G(auau) and B3LYP/6-31G(auau) level of theories. The density of states, HOMOs and LUMOs and absorption spectra of all the compounds under study have been computed and discussed. The HOMOs are delocalized on aminotetrazole moiety in all the compounds. A comprehensible intra charge transfer has been observed from aminotetrazole moiety to entire compounds. In the absorption spectra, the wavelength of maximum absorption for triplets in all the systems is red shifted relative to their corresponding singlet wavelengths of absorption maximum. The B3LYP/6-311G(auau) level of theory is found to give better results than B3LYP/6-31G(auau) level of theory, to reproduce previously reported experimental data. In most of the cases B3LYP/6-31G(auau) level of theory overestimate more the bond lengths.