FTIR: A Novel Bio-Analytical Technique

Abstract

Fourier Transform Infra Red (FTIR) spectroscopy is a magnificent technique. Infrared spectroscopy is based on the fact that molecules absorb specific frequencies that are characteristic to the structure. These absorptions are resonant frequencies of the absorbed radiation that matches with the frequency of the bond or group that vibrates. The energies are determined by the shape of the molecular potential energy surfaces, the masses of the atoms and the associated vibrational coupling. In particular, in the Born-Oppenheimer and harmonic hypothesis when the Molecular Hamiltonian corresponding to the electronic ground can be approximated by a harmonic oscillator in the neighborhood of the equilibrium molecular geometry, the resonant frequencies are determined by the normal modes corresponding to the molecular electronic ground state potential energy surface. The resonant frequencies can be related to the strength of the bond and the mass of the atoms. Thus, the frequency of the vibrations can be associated with a particular bond type.