OH-Stretch Vibrational Spectroscopy of Hydroxymethyl Hydroperoxide

We report measurement and analysis of the photodissociation spectrum of hydroxymethyl hydroperoxide (HOCH2OOH) and its partially deuterated analogue, HOCD2OOH, in the OH-stretching region. Spectra are obtained by Fourier transform infrared spectroscopy in the 1νOH and 2νOH regions, and by laser induced fluorescence detection of the OH fragment produced from dissociation of HOCH2OOH initiated by excitation of the 4νOH and 5νOH overtone regions (action spectroscopy). A one-dimensional local-mode model of each OH chromophore is used with ab initio calculated OH-stretching potential energy and dipole moment curves at the coupled-cluster level of theory. Major features in the observed absorption and photodissociation spectra are explained by our local-mode model. In the 4νOH region, explanation of the photodissocation spectrum requires a nonuniform quantum yield, which is estimated by assuming statistical energy distribution in the excited state. Based on the estimated dissociation threshold, overtone photodissociation is not expected to significantly influence the atmospheric lifetime of hydroxymethyl hydroperoxide.