Intramolecular hydrogen-bonding effects on O−H stretch overtone excitation for fluorinated hydroperoxides

Highlights: • Novel spectral simulations of OH overtone excitation in fluorinated hydroperoxides. • Intramolecular H-bonds prevent torsion about the O-O bond and simplify spectra. • Fluorinated hydroperoxides unlikely for overtone-induced atmospheric chemistry. - Abstract: Applying computational methods for predicting gas-phase O−H stretch overtone spectra to the series of fluorinated hydroperoxides CF₃OOH, CHF₂OOH, and CH₂FOOH reveals how intramolecular hydrogen bonding changes their overtone photochemistry, relative to their un-fluorinated analog CH₃OOH. Intramolecular hydrogen bonding between fluorine and the hydroxyl hydrogen atom decreases O−H stretch frequencies and raises the barrier for torsion about the O−O bond. Whereas O−O torsion accompanies O−H stretch overtone excitation for CH₃OOH, this is not the case for the fluorinated analogs that have intramolecular hydrogen bonding. The comparison highlights the molecular features that contribute to the feasibility of atmospheric overtone-induced O−O bond dissociation for CH₃OOH, but not for its fluorinated analogs.