Torsion-stretch coupling in the OH spectrum of cis-cis HOONO

PHYS 567

Matthew K. Sprague, sprague@caltech.edu1, Anne B. McCoy, mccoy@chemistry.ohio-state.edu2, Andrew K. Mollner1, and Mitchio Okumura, mo@its.caltech.edu1. (1) Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Division of Chemistry and Chemical Engineering, M/S 127-72, Pasadena, CA 91125, (2) Department of Chemistry, The Ohio State University, 100 W. 18th Ave., Columbus, OH 43210
The lowest energy conformer of peroxynitrous acid, cis-cis HOONO, forms a ring structure with an internal hydrogen bond. Because of this hydrogen bond, the OH stretch frequency and band intensity are dependent on the dihedral angles HOON and OONO. The torsional motions about these angles have comparable frequencies and are coupled. Previous calculations explicitly treated the OH stretch and the HOON torsion. We extended the previous treatments in order to examine the importance of the remaining OONO torsional mode. The minimum energy path along the two dihedral angles of HOONO was computed at the CCSD(T)/cc-pVTZ level. The potential energy surface was then computed as a function of the two dihedral angles and of the OH bond length. Vibrational levels were obtained using the vibrationally adiabatic approximation. Torsional coupling leads to a blue shift in OH stretch intensity, affecting the spectrum and kinetic analysis of HOONO.
 

PHYS Poster Session - Computational Spectroscopy and Reaction Dynamics
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