Infrared spectroscopy of transformic acid in solid parahydrogen

PHYS 377

Leif O. Paulson, lpaulson@uwyo.edu, Department of Chemistry, University of Wyoming, 1000 E. University Ave., Laramie, WY 82071-3838 and David T. Anderson, danderso@uwyo.edu, Department of Chemistry, The University of Wyoming, 1000 East University Drive, Laramie, WY 82071-3838.
We have initiated a systematic program of using solid parahydrogen as a host for high-resolution vibrational studies of polyatomic molecules. As a first step, the vibrational spectrum of trans-formic acid (FA) is presented. FA only contains five atoms, but it has two rotamers, cis and trans. In principle therefore, FA offers the possibility of studying conformational effects as well. We present spectroscopic measurements for 6 of the 9 vibrational modes of trans-FA. One complication revealed by these studies is that FA preferentially clusters with residual orthohydrogen present in the host. However, for the carbonyl stretching mode, the N=0-5 orthohydrogen cluster peaks are readily assigned and the small vibrational shifts quantified. Recent studies in another laboratory have revealed a unique process for promoting rotamer conversion by exciting vibrations of the hydrogen host itself, and these results may lead to a general method for studying vibrational spectra of high energy conformers.
 

PHYS Poster Session - General Experiment
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster

Division of Physical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008