title: Vibrational overtone spectrum of matrix isolated cis, cis-HOONO.
abstract: Cis, cis-peroxynitrous acid is known to be an intermediate in atmospheric reactions between OH and NO2 as well as HOO and NO. The infrared absorption spectra of matrix-isolated cc-HOONO and cc-DOONO in argon have been observed in the range of 500-8000 cm-1. Besides the seven fundamental vibrational modes that have been assigned earlier for this molecule [Zhang et al., J. Chem. Phys. 124, 084305 (2006)], more than 50 of the overtone and combination bands have been observed for cc-HOONO and cc-DOONO. Ab initio CCSD(T)/atomic natural orbital anharmonic force field calculations were used to help guide the assignments. Based on this study of the vibrational overtone transitions of cis, cis-HOONO that go as high as 8000 cm-1 and the earlier paper on the vibrational fundamentals, we conclude that the CCSD(T)/ANO anharmonic frequencies seem to correct to +/-35 cm-1. The success of the theoretically predicted anharmonic frequencies {upsilon} in assigning overtone spectra of HOONO up to 8000 cm-1 suggests that the CCSD(T)/ANO method is producing a reliable potential energy surface for this reactive molecule.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA. xu.zhang@jpl.nasa.gov
authors.forename: Xu
authors.initials: X
authors.lastname: Zhang
authors.forename: Mark R
authors.initials: MR
authors.lastname: Nimlos
authors.forename: G Barney
authors.initials: GB
authors.lastname: Ellison
authors.forename: Mychel E
authors.initials: ME
authors.lastname: Varner
authors.forename: John F
authors.initials: JF
authors.lastname: Stanton