Overtone Spectroscopy of Sulfonic Acid Derivatives

Abstract

Vapor-phase OH-stretching overtone spectra of methanesulfonic acid and trifluoromethanesulfonic acid were recorded in the Deltav(OH) = 4 and 5 regions using cavity ring-down spectroscopy. We compare these spectra to those of sulfuric acid to consider the effect on vibrational overtone spectra of replacing one of the OH groups with a more or less electronegative group. We complement our experimental work with anharmonic oscillator local mode calculations of the OH-stretching frequencies and intensities. The presence of a weak intramolecular interaction between the hydrogen atom of the OH group and the oxygen atom of the adjacent S=O group in methanesulfonic acid lowers its OH-stretching frequency from what would otherwise be predicted based on the electronegativity of the methyl group.

Dynamics and spectroscopy of vibrational overtone excited glyoxylic acid and 2,2-dihydroxyacetic acid in the gas-phase

“…37,71,95,118 CRD lengthens the interaction time of the sample and light using high reflectivity mirrors, which contain the laser pulse in the cell with the sample to increase the number of absorption transitions that occur. Two sets of mirrors were necessary to observe the spectra.…”

HSO3Cl: a prototype molecule for studying OH-stretching overtone induced photodissociation

“…34 Using a simple one-dimensional anharmonic oscillator local model, the overtone spectra of sulfuric acid derivatives have been computed, which found that excitation of the OH-stretching transition with ∆v ≥ 4 and ∆v ≥ 5, will provide sufficient energy for photodissociation of HSO 3 Cl and HSO 3 F, respectively. 29,34,35 Finally, ab initio molecular dynamics (MD) simulations have demonstrated that the decomposition of these derivatives, similar to what has been proposed to H 2 SO 4 , is possible via excitation of higher OH-stretching overtone transitions. 29,34 At the semi-empirical PM3 level, it was found that for HSO 3 Cl, excitation of v ≥ 4, or v ≥ 5 (PM3) can induce the elimination reaction.…”

“…29,34,35 Finally, ab initio molecular dynamics (MD) simulations have demonstrated that the decomposition of these derivatives, similar to what has been proposed to H 2 SO 4 , is possible via excitation of higher OH-stretching overtone transitions. 29,34 At the semi-empirical PM3 level, it was found that for HSO 3 Cl, excitation of v ≥ 4, or v ≥ 5 (PM3) can induce the elimination reaction. 34 For photodissociation of HSO 3 F excitation of the v ≥ 7 OH-stretching state is necessary with PM3, whereas excitation of the v ≥ 5 overtone is sufficient at the MP2/TZP level.…”

Cavity Enhanced Spectroscopy: Applications Theory and Instrumentation

“…A number of further experiments have sought to characterize overtone absorptions for trace compounds where absorption in these bands may be related to reactivity through overtone-induced photolysis. (29) Studies have focused primarily on compounds with O-H stretches, such as organic and inorganic acids, where overtones up to v OH = 5 have been commonly measured (30,31) . A few measurements of C-H overtones in volatile organic compounds have also been made, such as alkanes (32) and highly reactive alkenes, including isoprene.…”