SEARCH Articles Figures Tables Density Functional Theory vibrational spectroscopy Density function theory vibrational spectra Density functional theory , vibrational Density functional theory vibrational circular dichroism Density functional theory vibrational frequency convergence Elementary Theory of Vibrational Spectroscopy Group theory and molecular vibration Harmonic vibrations classical theory Intramolecular vibrational energy relaxation theory Lattice vibrations harmonic theory Linear response theory, vibrational modes Molecular vibrations, theory Multi-phonon theory of vibrational relaxation Nanotubes vibrations, theory Odor vibrational theory Perturbation theory anharmonic vibrational spectroscop Perturbation theory bending vibrations RRKM theory rotational-vibrational energy transfer RRKM theory vibrational frequencies Relaxation, vibrational quantum theory Second-order vibrational perturbation theory Second-order vibrational perturbation theory energy levels Second-order vibrational perturbation theory excited electronic states Theory of Harmonic Vibrations Theory of Molecular vibrations Tunnel effect theory vibrational mode coupling Variational transition state theory vibrator Vibrational Raman effect, classical theory Vibrational circular dichroism theory Vibrational dynamics coupling theory Vibrational energy theory Vibrational line shape theory Vibrational methods perturbation theory Vibrational perturbation theory Vibrational spectra, theory Vibrational spectroscopy, theory Vibrational transition state theory Vibrationally adiabatic theory Vibrationally enhanced ground state tunneling theory Zero point vibrational energy transition state theory