Atmospheric fate of several alkyl nitrates Part 2UV absorption cross-sections and photodissociation quantum yields

Abstract

The UV absorption cross-sections of methyl, ethyl and isopropyl nitrate between 233 and 340 nm have been measured using a diode array spectrometer in the temperature range 240–360 K. The absorption cross-sections of these alkyl nitrates decrease with increasing wavelength and decrease with decreasing temperature for λ>280 nm. The photodissociation quantum yield for CH₃ONO₂ to produce NO₂ and CH₃O was found to be essentially unity at 248 nm using transient UV absorption methods. Production of O and H atoms in the photodissociation of methyl nitrate at 248 and 308 nm were found to be negligible using resonance fluorescence detection of the atoms. High quantum yields for O atoms were measured following 193 nm photolysis of methyl nitrate. The OH radical was measured to be a photoproduct with a very small quantum yield. Using the OH rate coefficients reported in the accompanying paper and the UV absorption cross-sections and the photodissociation quantum yields measured here, the first-order rate constants for atmospheric loss of methyl, ethyl and isopropyl nitrate were calculated. Photolysis was found to be the dominant atmospheric loss process for the three alkyl nitrates.

References

1. R. K. Talukdar, S. Herndon, J. B. Burkholder, J. M. Roberts and A. R. Ravishankara, J. Chem. Soc., Faraday Trans., 1997, 93, 2787.
2. J. M. Roberts, Atmos. Environ. A, 1990, 24, 243.
3. J. M. Roberts and R. W. Fajer, Environ. Sci. Technol., 1989, 23, 945.
4. L. E. Harris, J. Chem. Phys., 1973, 58, 5615.
5. O. Rattigan, E. Lutman, R. L. Jones, R. A. Cox, K. Clemitshaw and J. Williams, J. Photochem. Photobiol., A: Chem., 1992, 66, 313.
6. O. Rattigan, E. Lutman, R. L. Jones, R. A. Cox, K. Clemitshaw and J. Williams, J. Photochem. Photobiol., A: Chem., 1992, 69, 125.
7. K. C. Clemitshaw, J. Williams, O. Rattigan, D. E. Shallcross, K. S. Law and R. A. Cox, J. Photochem. Photobiol., A: Chem., 1997, 102, 117.
8. L. Zhu and C.-F. Ding, Chem. Phys. Lett., 1997, 265, 177.
9. R. E. Rebbert, J. Phys. Chem., 1963, 67, 1923.
10. J. B. Burkholder, R. K. Talukdar, A. R. Ravishankara and S. Solomon, J. Geophys. Res., 1993, 98, 22937.
11. R. K. Talukdar, G. L. Vaghjiani and A. R. Ravishankara, J. Chem. Phys., 1992, 96, 8194.
12. R. F. Warren, T. Gierczak and A. R. Ravishankara, Chem. Phys. Lett., 1991, 183, 403.
13. R. J. Yokelson, J. B. Burkholder, R. W. Fox, R. K. Talukdar and A. R. Ravishankara, J. Phys. Chem., 1994, 98, 13144.
14. A. R. Ravishankara, P. H. Wine, C. A. Smith, P. E. Barbone and A. Torabi, J. Geophys. Res., 1986, 91, 5355.
15. W. B. DeMore, S. P. Sander, D. M. Golden, R. F. Hampson, M. J. Kurylo, C. J. Howard, A. R. Ravishankara, C. E. Kolb and M. J. Molina, Chemical Kinetics and Photochemical Data for use in Stratospheric Modeling, JPL publication 94-36', Jet Propulsion Laboratory, Pasadena, CA, 1994.
16. G. L. Vaghjiani, A. A. Turnipseed, R. F. Warren and A. R. Ravishankara, J. Chem. Phys., 1992, 96, 5878.
17. M. P. Turberg, D. M. Giolando, C. Tilt, T. Soper, S. Mason, M. Davies, P. Klingensmith and G. A. Takacs, J. Photochem. Photobiol., A: Chem., 1990, 51, 281.
18. M. J. Frost and I. W. M. Smith, J. Chem. Soc., Faraday Trans., 1990, 86, 1751.
19. L. Batt, R. T. Milne and R. D. McCulloch, Int. J. Chem. Kinet., 1977, 9, 567.
20. A. Bongartz, J. Kames, F. Welter and U. Schurath, J. Phys. Chem., 1991, 95, 1076.
21. D. Hsu, D. L. Mont and R. N. Zare, Spectral Atlas of Nitrogen Dioxide, 553 to 648 nm, Academic Press, New York, 1978.
22. M. Zelikoff and L. M. Aschenbrand, J. Chem. Phys., 1954, 22, 1685.
23. H. Meyrahn, J. Pauly, W. Schneider and P. Warneck, J. Atmos. Chem., 1986, 4, 277.
24. S. A. McKeen, T. Gierczak, J. B. Burkholder, P. O. Wennberg, T. F. Hanisco, E. R. Keim, R.-S. Gao, S. C. Liu, A. R. Ravishankara and D. W. Fahey, Geophys. Res. Lett., 1997, submitted for publication.
25. P. Gray and G. T. Rogers, J. Chem. Soc., Faraday Trans., 1954, 50, 28.
26. J. A. Gray and D. W. G. Style, Trans. Faraday Soc., 1953, 49, 52.
27. W. T. Luke, R. R. Dickerson and L. J. Nunnermacker, J. Geophys. Res., 1989, 94, 14.
28. W. T. Luke and R. R. Dickerson, Geophys. Res. Lett., 1988, 15, 1181.
29. A. M. Renlund and W. M. Trott, Chem. Phys. Lett., 1984, 107, 555.
30. X. Yang, P. Felder and J. R. Huber, J. Phys. Chem., 1993, 97, 10903.
31. ‘U.S. Standard Atmospheres, 1976’, NOAA/NASA/USAF, 1976.
32. J. A. Kerr and D. W. Stocker, J. Atmos. Chem., 1986, 4, 253.
33. O. J. Nielsen, H. W. Sidebottom, M. Donlon and J. Treacy, Chem. Phys. Lett., 1991, 178, 163.