A force field analysis of the methyl radical X̃ 2A″2 state stretching potential using the local mode—coupled Morse oscillator model

Abstract

The local mode-coupled Morse oscillator model was utilized to determine the quadratic, cubic, and quartic force constants for the vibrational stretching potential energy functions of the CH3, CD3, CH2D, and CHD2 using stretching fundamentals and overtones derived from resonance Raman studies. The Morse harmonic frequency and anharmonic constant of the methyl radical indicate that bonding in the methyl radical and a variety of ethylenic molecules is primarily a function of the sp2 hybridization of the central atom and that the bonding is not extensively influenced by the methyl radical’s unpaired electron or the π bonding in the ethylenic molecules. The vibrational states of the methyl radical are best described by wave functions containing significant amounts of normal mode character. The stretching frequencies for the tritiated methyl radical isotopomers are calculated.