Photodissociation of an alkyl nitrite at a liquid surface: flight-time distributions of NO and HNO

The photochemistry at a gas–liquid interface was investigated by time-of-flight quadrupole mass spectroscopy. A liquid film of dodecyl dinitrite (ONO(CH2)12ONO), dissolved in squalane (C30H62), was irradiated with low-fluence laser pulses at 275 and 355 nm. The translational temperature of most NO and all HNO desorbate is in equilibrium with the liquid. A quantitative simulation requires that diffusion and radical reactions in the liquid are included. Ejection of hyperthermal NO (Ttrans=500–2200 K) was also observed. The results are compared to those of alkyl nitrite monomers, clusters and solid films.