Torsional IR spectra of three conformers of the resorcinol molecule

Abstract

Conformational states, barriers to internal rotation, 2D potential energy surfaces, kinetic coefficients and dipole moment components of the resorcinol molecule are calculated at the MP2/CBS(T,Q), MP2/Aug-cc-pVTZ, MP2/dAug-cc-pVTZ and B3LYP/Aug-cc-pVTZ levels of theory. Using the calculated data sets, the energies and wave functions of stationary torsional states were determined for the first time using a numerical solution of the vibrational Schrödinger equation of limited dimensionality. This made it possible to establish the values of the tunneling splitting of the ground vibrational and a number of excited torsional states of the energetically most preferred conformer of the molecule, belonging to the point symmetry group CS. The 100 lowest torsional states of the resorcinol molecule are classified according to the symmetry species of the molecular symmetry group C2V(M). The torsional IR spectra of three conformers of the molecule were simulated at different temperatures. The calculated values of the frequency of the most intense torsional vibration in the most stable conformer of the molecule (316 cm−1) is in good agreement with the experimental value of the frequency of this vibrations (318 cm−1), obtained in [W.G. Fateley, J.Phys.Chem., 79 (1975) 199–204.]