Study of H+NO2 in an Argon Matrix between 4 and 14°K; The Infrared Spectra of Matrix-Isolated cis- and trans-HONO

Abstract

The matrix-isolated infrared spectra of cis- and trans-nitrous acid molecules have been obtained in argon at low temperatures by the reaction of H atoms with NO2. The spectra, which include 15N- and 18O-substituted molecules, are not complicated by the stabilization of the acid in the presence of large concentrations of NO, NO2, and H2O. All six fundamentals of the cis and three of the trans isomers have been identified, and found generally to confirm the assignments of a previous study where some uncertainty did exist. The normal coordinate calculation performed for the cis molecule predicted the average frequencies of the four 15N- and 18O-substituted species with an error of 0.60 cm−1 or 0.068%.

Light induced transformations of small nitroso compounds in low temperature rare gas matrices

“…are extremely weak and are located at 2566 cm -I for the cis species and at 2613 cm -I for trans isomer. The torsional frequency is higher in the cis isomer, paralleling the findings in HONO [160,161].…”

“…In a comprehensive IR analysis of seven nitrous acid isotopic modifications in the gas and solid phase McGraw et al [159] determined the force fields of the isomers. The cis force field was extended by Guillory and Hunter [160], who produced nitrous acid in argon matrices using a recombination reaction between NO 2 and H. The H atoms were generated by VUV photolysis of matrix isolated H20 , CH4, or HCI. Complete substitution structures were subsequently determined by Cox et al [161,162].…”

Thermochemistry for enthalpies and reaction paths of nitrous acid isomers

“…Matrix studies [56] have reported that only cis-and trans-HONO are produced in the reaction H + NO 2 despite the theoretical prediction [57], which suggested that HNO 2 should be formed rather than HONO.…”

Chemical Reactions of H and D Atoms with NO2 and CINO, a Crossed Molecular Beam Study

“…From the rotational energies of The lifetime of the complex must be longer than one rotational period, otherwise one would have a forwardbackward asymmetry. From the known [ 5 ] rotational constants of HONO and DONO. and the average angular momenta cited above, one calculates a rotation time of 3 to 5 psec.…”

“…When the reaction is performed in solid argon at low temperatures, the product HONO is formed. suggesting that this is an intermediate [5]. One chemoluminescence [6] and two laser induced fluorescence studies [7.8] have been published.…”