Evidence of Vibrational Mode-Coupling in 2-Fluoroethanol via High ResolutionInfrared Spectroscopy in a Molecular Beam

摘要

The rotationally resolved high resolution spectrum of 2-fluoroethanol in amolecular beam has been measured in an effort to determine the extent of mode-selective vibrational coupling. The high resolution spectrum of an asymmetric CH stretch clearly demonstrates that mode-coupling is present in 2-fluoroethanol. The extent of mode-coupling is significantly less than would be predicted based on previous work on molecules of a similar size and density of states. The small amount of mode-coupling in the CH stretch is consistent with the slow photoisomerization rate of 2-fluoroethanol upon excitation of the CH stretch, and is evidence that supports mode-selective vibrational coupling in the isomerization reaction of 2-fluoroethanol.