Near-IR photodissociation of peroxy acetyl nitrate

S. A. Nizkorodov (1) , J. D. Crounse (2) , J. L. Fry (2) , C. M. Roehl (3, 4) , P. O. Wennberg (3, 4)

1 Department of Chemistry [Irvine]
2 Division of Chemistry and Chemical Engineering
3 EAS - Division of Engineering and Applied Science [Pasadena]
4 Division of Geological and Planetary Sciences [Pasadena]

Measurements of the C-H overtone transition strengths combined with estimates of the photodissociation cross sections for these transitions suggest that near-IR photodissociation of peroxy acetyl nitrate (PAN) is less significant (J_near-IR?3x10^-8s^-1 at noon) in the lower atmosphere than competing sinks resulting from unimolecular decomposition and ultraviolet photolysis. This is in contrast to the photochemical behavior of a related peroxy nitrate, pernitric acid (PNA), that undergoes rapid near-IR photolysis in the atmosphere with J_near-IR?10^-5s^-1 at noon (Roehl et al., 2002). This difference is attributed to the larger binding energy and larger number of vibrational degrees of freedom in PAN, which make 4?_CH the lowest overtone excitation with a high photodissociation yield (as opposed to 2?_OH in PNA).

Domaines: Océan, Atmosphère

S. A. Nizkorodov, J. D. Crounse, J. L. Fry, C. M. Roehl, P. O. Wennberg. Near-IR photodissociation of peroxy acetyl nitrate. Atmospheric Chemistry and Physics, 2005, 5 (2), pp.385-392. ⟨hal-00295603⟩