15min:

MING-WEI CHEN, GABRIEL M. P. JUST, TERRANCE J. CODD, TERRY A. MILLER, Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University, 120 W. 18th Avenue, Columbus, Ohio 43210; W. LEO MEERTS, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, NL-6525 AJ Nijmegen, The Netherlands.

The jet-cooled A--X origin band absorption spectra of the G₁G₂G₃ conformer of four -hydroxyethyl-peroxy ( -HEP) isotopologues, -HEP (HOCH₂CH₂OO), -DHEP (DOCH₂CH₂OO), -HEP-d₄ (HOCD₂CD₂OO), -DHEP-d₄ (DOCD₂CD₂OO), have been recorded by a cavity ringdown apparatus with a laser source linewidth 70 MHz in the near IR region. The spectra of all four isotopologues have been analyzed and successfully simulated with an evolutionary algorithm, confirming the cyclic structure of the conformer responsible for the observed origin band. In addition, rotational constants in both the X and A states and the orientation of the transition dipole moment have been determined. The broadened linewidth of the absorption spectrum ( > 2~GHz) is due to the shortened lifetime of the A state following its internal conversion back to the X state. The variation of lifetime with deuteration suggests that the hydroxyl hydrogen is involved and the process likely occurs along the reaction path for conversion between the peroxy and peroxide isomers.