The hydroxyl radical (OH) is the most important oxidant in the troposphere and impacts the abundance of greenhouse gases and pollutants. The objective of this research project is to explore non-photolytic routes to atmospheric OH. Ozonolysis of alkenes yields stabilised Criegee intermediates (CIs), which will be identified by IR action spectroscopy; IR excitation of CIs produces OH that is detected by UV laser-induced fluorescence. Changes in the IR-UV time delay quantify OH production rates. Rates are isomer and conformer specific and comparison with calculated rates enables identification of the exact reaction pathway. Stabilised CIs also react with atmospheric species, and these reactions will be explored. During alkane combustion, hydroperoxy radicals (QOOH) form. Direct observations of QOOH are scarce; however, IR action spectroscopy allows the characterisation of QOOH intermediates and their ability to release OH.
