Vibrational Spectra(Theoretical, Experimental) and Optimized Structure, Frontire Molecular Orbital, Mulliken Atomic Charge Studies on Pentylenetetrazole (PTZ) Based on Density Functional Theory

Abstract

The vibrational spectra of Pentylenetetrazole (PTZ) have been recorded in the regions 4000−400 cm^-1for FT-IR and 3500−100 cm^-1 for FT-Raman. The molecular structure, geometry optimization, vibrational frequencies were obtained by the density functional theory (DFT) using B3LYP method with 6-31G and 6-311+G  basis sets. The complete assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes, calculated and the scaled values were compared with experimental FT-IR and FT-Raman spectra. The HOMO and LUMO energy gap reveals that the energy gap reflects the chemical activity of the molecule. The dipole moment (m), polarizability (α), anisotropy polarizability (Δα) and first hyperpolarizability (β_tot) of the molecule have been reported. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by  molecular electrostatic potential (MEP).