Quantum mechanical studies and vibrational analysis of some organic molecules using density functional theory

Abstract

Spectroscopy is the study of electromagnetic spectra the wavelength composition of light due to atomic and molecular interactions. Spectroscopy is used in physical and analytical chemistry because atoms and molecules have unique spectra. As a result, these spectra can be used to detect, identify, and quantify information about the atoms and molecules. It is the most sensitive instrument accessible to the researchers for exploring the world of atoms and molecules. Vibrational spectroscopy is a collective term used to describe two analytical techniques namely Infrared and Raman spectroscopy. These techniques are used to measure the vibrational energy levels in a sample. These energy levels are associated with the chemical bonds in the sample. Infrared spectroscopy has been a workhorse technique for material analysis in the laboratory for over seventy years. An infrared spectrum represents a fingerprint of a sample with absorption peaks which correspond to the frequencies of vibrations between the bonds of the atoms making up the material. Because each different material is a unique combination of atoms, no two compounds produce the exact same infrared spectrum. Therefore, infrared spectroscopy can result in a positive identification (qualitative analysis) of every different kind of material. In addition, the size of the peaks in the spectrum is a direct indication of the amount of material present. With modem software algorithms, infrared is an excellent tool for quantitative analysis. newline