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 Title: A THEORETICAL CHARACTERIZATION OF ELECTRONIC STATES OF CH2IOO AND CH2OO RADICALS RELEVANT TO THE NEAR IR REGION Author(s): Dawes, Richard Contributor(s): Miller, Terry A.; Kline, Neal; Huang, Meng; Lolur, Phalgun Subject(s): Atmospheric science Abstract: Criegee intermediates (R$_{1}$R$_{2}$COO or CIs) arise from ozonolysis of biogenic and anthropogenic alkenes, which is an important process in the atmosphere. Recent breakthroughs in producing them in the gas phase have resulted in a flurry of experimental and theoretical studies. Producing the simplest CI (CH$_{2}$OO) in the lab via photolysis of CH$_{2}$I$_{2}$ in the presence of O$_{2}$ yields both CH$_{2}$OO and CH$_{2}$IOO with pressure dependent branching. As discussed in the preceding talk, both species might be expected to have electronic transitions in the near IR (NIR). Here we discuss electronic structure calculations used to characterize the electronic states of both systems in the relevant energy range. Using explicitly-correlated multireference configuration interaction (MRCI-F12) and coupled-cluster (UCCSD(T)-F12b) calculations we were first able to exclude CH$_{2}$OO as the carrier of the observed NIR spectrum. Next, by computing frequencies and relaxed full torsional scans for the ~{A} and ~{X} states, we were able to aid in analysis and assignment of the NIR spectrum attributed to CH$_{2}$IOO. Issue Date: 26-Jun-15 Publisher: International Symposium on Molecular Spectroscopy Citation Info: ACS Genre: CONFERENCE PAPER/PRESENTATION Type: Text Language: English URI: http://hdl.handle.net/2142/79442 Date Available in IDEALS: 2016-01-05
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