UV absorption spectrum of the C2 Criegee intermediate CH3CHOO

Mica C Smith; Wei-Lun Ting; Chun-Hung Chang; Kaito Takahashi; Kristie A Boering; Jim Jr-Min Lin

doi:10.1063/1.4892582

UV absorption spectrum of the C2 Criegee intermediate CH3CHOO

J Chem Phys. 2014 Aug 21;141(7):074302. doi: 10.1063/1.4892582.

Authors

Mica C Smith¹, Wei-Lun Ting², Chun-Hung Chang², Kaito Takahashi², Kristie A Boering¹, Jim Jr-Min Lin²

Affiliations

¹ Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, USA.
² Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.

PMID: 25149781
DOI: 10.1063/1.4892582

Abstract

The UV spectrum of CH3CHOO was measured by transient absorption in a flow cell at 295 K. The absolute absorption cross sections of CH3CHOO were measured by laser depletion in a molecular beam to be (1.06 ± 0.09) × 10(-17) cm(2) molecule(-1) at 308 nm and (9.7 ± 0.6) × 10(-18) cm(2) molecule(-1) at 352 nm. After scaling the UV spectrum of CH3CHOO to the absolute cross section at 308 nm, the peak UV cross section is (1.27 ± 0.11) × 10(-17) cm(2) molecule(-1) at 328 nm. Compared to the simplest Criegee intermediate CH2OO, the UV absorption band of CH3CHOO is similar in intensity but blue shifted by 14 nm, resulting in a 20% slower photolysis rate estimated for CH3CHOO in the atmosphere.