Infrared spectrum of chloromethyl hydroperoxide CH2ClOOH produced from reaction of the criegee intermediate CH2OO with HCL

Liang, Wei-Che

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https://hdl.handle.net/2142/100664 Copy

Description

Title

Infrared spectrum of chloromethyl hydroperoxide CH2ClOOH produced from reaction of the criegee intermediate CH2OO with HCL

Author(s)

Liang, Wei-Che

Contributor(s)

Lee, Yuan-Pern

Issue Date

2018-06-22

Keyword(s)

Vibrational structure/frequencies

Abstract

The Criegee intermediates, which are carbonyl oxides produced in ozonolysis of unsaturated hydrocarbons,a play important roles in the production of OH, aerosols and organic acids in the atmosphere. Criegee intermediates react readily with other atmospheric species such as NO2, SO2, (H2O)2 and HCl. The reaction of CH2OO with HCl was reported to be rapid, with a rate coefficient of 4.6×10−11 cm3 molecule−1 s −1 . b Quantum-chemical calculations indicate that the reaction CH2OO + HCl proceeds through a barrierless association reaction to form chloromethyl hydroperoxide (CMHP, CH2ClOOH), which was predicted to have three stable conformations, denoted as gauche-gauche CMHP, anti-CMHP and gauche-anti CMHP; the first two conformers were observed by microwave spectroscopy.c In this work, a step-scan Fourier-transform spectrometer coupled with a multipass absorption cell was employed to record temporally resolved infrared (IR) absorption spectra of the reactants and products during the reaction of CH2OO with HCl in a flow system. CH2OO was produced from the reaction of O2 with CH2I, which was produced via photolysis of CH2I2 at 308 nm.d Time-resolved IR absorption spectra were recorded at resolution 0.25 cm−1 . The spectrum of gauche-gauche CMHP was characterized by the absorption bands at 1061.4, 1309.4, 1359.9 cm−1 , and the spectrum of gauche-anti CMHP was characterized by the absorption bands at 1054.8, 1310.3, 1359.3 cm−1 . The observed wavenumbers, rotational contours and relative intensities agree with those predicted with the B3LYP/aug-cc-PVTZ method; contributions of the hot bands from excited states of the low-lying torsional modes are significant.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/100664

DOI

10.15278/isms.2018.FA02

Copyright and License Information

Copyright 2018 Wei-Che Liang

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