Using He droplets for measurements of interconversion enthalpy of conformers in 2-chloroethanol

Abstract

2-chloroethanol molecules having temperature from 300 to 600 K have been captured by helium droplets and the infrared spectra of the O-H and C-H stretching bands of the embedded molecules have been obtained. The intensity ratio of the bands due to trans and gauche conformers of the molecules follows the Arrhenius dependence, giving the enthalpy of conformers interconversion of 1.1 kcal/mol. It is concluded that the abundance ratio of the conformers, which are at equilibrium in the gas phase, remains unchanged upon the rapid cooling of the molecules in the helium droplets. © 2009 American Institute of Physics.