Observation of the Ã−X̃ Electronic Transition of the 1-C₃H₇O₂ and 2-C₃H₇O₂ Radicals Using Cavity Ringdown Spectroscopy

Abstract

Cavity ringdown spectra of the A-X electronic transition of the 1-propyl and 2-propyl peroxy radicals are reported. Spectroscopic assignments are facilitated by implementing several production mechanisms, either isomer-specific or not. Assignments of specific spectral lines to particular conformers of a given isomer are suggested. Observations on the temporal decay of the various species are reported.

The OH-Initiated Oxidation of 1,3-Butadiene in the Presence of O2 and NO: A Photolytic Route To Study Isomeric Selective Reactivity

“…10,13,14 Figure 9 shows normalized sensitivity coefficients for all the rate constants in the abridged reaction mechanism evaluated at 30 µs and NO and O 2 concentrations of 6.49 × 10 14 and 8.40 × 10 14 molecules cm -3 , respectively. The figure demonstrates that the OD concentration profiles depend sensitively on few rate constants, in particular, the relative branching between R-hydroxyalkyl and -hydroxyalkyl radicals (k 1 and k 2 ), 61 the rate of O 2 reaction with R-hydroxyalkyl radicals (k 3 ), the rate constant for the reaction between NO and DO 2 (k 13 ), and the rate between OD and 1-iodo-3-buten-2-ol (k 16 ). The rate constant between NO and DO 2 (k 13 ) is well established as 1.1(0.4 × 10 -11 cm 3 molecules -1 s -1 , 62,63 and we have determined a rate constant of 1.5(0.1 × 10 -11 cm 3 molecules -1 s -1 for the reaction between OD and the photolytic precursor (k 16 ) in the present work.…”

“…Zalyubovsky and co-workers have recently demonstrated the feasibility of using cavity ring-down spectroscopy on the resolved A-X transition of peroxy radicals to obtain selective detection. 16 In those studies, the peroxy radicals were generated via reaction of a hydrocarbon with OH in the presence of O 2 . As the hydrocarbons become more complex and the resulting number of isomers increases, however, the spectroscopic assignments will be challenging.…”

Near-IR Cavity Ringdown Spectroscopy and Kinetics of the Isomers and Conformers of the Butyl Peroxy Radical

“…5,6,8 Briefly the second harmonic light from an Nd:YAG laser pumped a dye laser (20 Hz QuantaRay PRO-270 Nd:YAG, Spectra Physics SIRAH dye laser). The dyes used were DCM, Rhodamine B, and Rhodamine 101.…”

“…For the peroxy radicals, where R is a simple alkyl group, we have reported NIR CRDS with R=CH 3 , 5 C 2 H 5 , 5 1-and 2-C 3 H 7 . 6,7 Larger alkanes play significant roles in both combustion and atmospheric chemistry. It is therefore worthwhile examining the A − X spectra of the corresponding RO 2 radicals.…”

Spectroscopy of free radicals and radical containing entrance-channel complexes in superfluid helium nanodroplets

“…At pyrolysis temperatures of about 1000 K, the peak at 3774 cm −1 appears which is assigned to the HF-Ethyl radical complex. spectra of these molecules have been difficult to obtain in free-jet expansions, though [183][184][185][186][187][188].…”