Matrix Isolation Vibrational Spectroscopy of Methyl Pernitrite

Reactions between organic peroxyl radicals (ROO·) and NO are important sources of NO2 in the atmosphere. Methyl pernitrite is the reactive intermediate in CH3OO· + NO ↔ [CH3OONO] ↔ CH3O· + NO2. However, the CH3OONO intermediate can also isomerize to methyl nitrate (CH3ONO2). The subsequent decomposition of CH3OONO determines the branching ratio between organic nitrate and NO2 formation. Methyl pernitrite and its deuterated analogue CD3OONO have been synthesized and isolated in a low temperature Ar matrix. Harmonic and anharmonic CCSD(T) vibrational frequencies are used to aid the spectral assignments. Atmospheric implications for in situ organic nitrate production as well as branching ratios in higher order organic peroxyl reactions will be discussed.