Vibrational Spectroscopic Studies, Homo-Lumo Analysis of 1-Methyl Isoquinoline

Abstract

         The Fourier transform infrared (FTIR) and (FT-Raman spectra of 1-methylisoquinoline (1-MIQ ) have been recorded in the region 4000-400cm^-1and3500-50cm^-1, respectively Utilizing the observed FTIR and FT-Raman data, a complete vibrational assignment and analysis of fundamental  modes of the compound have been carried out. The optimum molecular geometry, harmonic vibrational frequency ,infrared  intensity and Raman scattering activities, have been calculated by density functional theory (DFT/HF)methods with 6-31+G(d,p) and 6-311++G(d,p) basis set. The difference  between the observed  and scaled wave number values of most of the fundamentals is very small. A detailed interpretation of the infrared and Raman spectra of 1-MIQ is also reported based on total energy distribution (TED). The calculated HOMO and LUMO energies show that charge transfer occur within the molecule.