Reactions of atomic carbon, C[2 (³P _J)],with dienes and diynes investigated by time-resolved atomic resonance absorption spectroscopy in the vacuum ultraviolet

Abstract

Absolute data for the collisional removal of ground-state atomic carbon, C[2 (³P_J)], generated by pulsed irradiation and monitored by time-resolved atomic resonance absorption spectroscopy in the vacuum ultraviolet, have been determined for reaction with a range of dienes and diynes. The precursor of atomic carbon was C₃O₂ (λ>ca. 160 nm), photolysed in the presence of excess helium buffer gas and the added reactant gases in a slow flow system, kinetically equivalent to a static system. C(2³P_J) was then monitored photoelectrically at λ=166 nm (3³P_J←2³P_J) with data capture and signal averaging of complete atomic profiles by a transient digitiser with direct computer interfacing for kinetic analysis. The following absolute second-order rate constants (k_R/c molecule^-1 s^-1, 300 K) for the reactions of ground-state carbon atoms with the various organic targets have been measured: allene, 8.0±0.1×10^-10; buta-1,3-diene, 1.1±0.1×10^-9; penta-1,4-diene, 1.2±0.1×10^-9; hexa-1,5-diene, 1.2±0.1×10^-9; hepta-1,6-diene, 1.2±0.1×10^-9; octa-1,7-diene, 1.2±0.1×10^-9; nona-1,8-diene, 1.3±0.1×10^-9; deca-1,9-diene, 1.4±0.1×10^-9; octa-1,7-diyne, 1.1±0.1×10^-9; nona-1,8-diyne, 1.1±0.1×10^-9. These absolute rate data are compared with data reported hitherto for the reaction of C(2³P_J) with the analogous mono-alkenes and mono-alkynes. The large value of the rate constants for reactions of C(2³P_J) with both the mono- and di-organic species indicate cross-sections which are sufficiently large to be included in the modelling of interstellar clouds characterised by low temperatures and densities, an aspect of this work which is considered.

References

1. D. R. Flower, Int. Rev. Phys. Chem., 1995, 14, 421.
2. J. R. Heath and R. J. Saykally, Science, 1996, 274, 1480.
3. Nat. Bur. Stand. Circ. 467, Atomic Energy Levels, ed. C. E. Moore, US Government Printing Office, Washington, DC, 1949, vol. I, pp. 21–23.
4. A. L. Cooksy, R. J. Saykally, J. M. Brown and K. M. Evenson, Astrophys. J., 1986, 309, 828.
5. R. J. Saykally and K. M. Evenson, Astrophys. J., 1980, 238, 107.
6. H. Nussbaumer, Astrophys. J., 1971, 166, 411.
7. R. J. Garstang, Mon. Not. Astronom. Soc., 1951, 111, 115.
8. M. A. Frerking, K. Keene, G. E. Black and T. G. Phillips, Astrophys. J., 1989, 344, 311.
9. R. Genzel, A. I. Harris, T. J. Jaffe and J. Stutki, Astrophys. J., 1988, 332, 1049.
10. J. Keene, G. A. Blake, T. G. Phillips, P. J. Huggins and C. A. Beichman, Astrophys. J., 1985, 299, 967.
11. G. J. White and R. Padman, Nature (London), 1991, 354, 511.
12. J. Zmuidzinas, A. L. Betz, R. T. Boreika and D. M. Goldhaber, Astrophys. J., 1988, 355, 774.
13. J. Zmuidzinas, A. L. Betz and D. M. Goldhaber, Astrophys. J., 1986, 307, 75.
14. A. Dalgarno and J. H. Black, Rep. Prog. Phys., 1976, 39, 573.
15. W. W. Duley and D. A. Williams, Interstellar Chemistry, Academic Press, New York, 1984.
16. E. Herbst, in Rate coefficients in Astrochemistry, ed. T. J. Millar and D. A. Williams, Kluwer, Dordrecht, 1988, p. 239.
17. N. Haider and D. Husain, J. Chem. Soc., Faraday Trans., 1993, 89, 7.
18. N. Haider and D. Husain, J. Photochem. Photobiol., 1993, 70, 119.
19. N. Haider and D. Husain, Z. Phys. Chem., 1992, 176, 133.
20. N. Haider and D. Husain, Int. J. Chem. Kinet., 1993, 25, 423.
21. N. Haider and D. Husain, Ber. Bunsen-Ges. Phys. Chem., 1993, 97, 571.
22. N. Haider and D. Husain, Combust. Flame, 1993, 93, 327.
23. D. C. Clary, N. Haider, D. Husain and M. Kabir, Astrophys. J., 1994, 422, 416.
24. J. O. Hirschfelder, C. F. Curtiss and R. B. Bird, Molecular Theory of Gases and L iquids, Wiley, New York, 1954.
25. E. Herbst, H.-H. Lee, D. A. Howe and T. J. Millar, Mon. Not. R. Astronom. Soc., 1994, 268, 335.
26. R. I. Kaiser and A. G. Suits, Rev. Sci. Instrum., 1995, 66, 5405.
27. G. Dorthe, M. Costes, C. Naulin, J. Joussot-Dubien, C. Veaucamps and G. Nouchi, J. Chem. Phys., 1985, 83, 3171.
28. M. Costes, C. Naulin, G. Dorthe, G. Daleau, J. Joussot-Dubien, C. Lalaude, M. Vinckert, A. Destor, C. Veaucamps and G. Nouchi, J. Phys. E, 1989, 22, 1017.
29. R. I. Kaiser, C. Oschenfeld, M. Head-Gordon, Y. T. Lee and A. G. Suits, Science, 1996, 274, 1508.
30. R. I. Kaiser, Y. T. Lee and A. G. Suits, J. Chem. Phys., 1996, 105, 8705.
31. R. I. Kaiser, D. Stranges, Y. T. Lee and A. G. Suits, J. Chem. Phys., 1996, 105, 8721.
32. J. Takahashi and K. Yamashita, J. Chem. Phys., 1996, 104, 6613.
33. S. Taylor and D. Williams, Chem. Br., 1993, 129, 680.
34. M. R. Schofield, S. Goyal, J.-H. Choi and H. Reisler, J. Phys. Chem., 1995, 99, 14605.
35. D. C. Scott, F. Winterbottom, M. R. Scholefield, S. Goyal and H. Reisler, Chem. Phys. Lett., 1994, 222, 471.
36. S. A. Reid, F. Winterbottom, D. C. Scott, J. de Juan and H. Reisler, Chem. Phys. Lett., 1992, 189, 430.
37. H. H. Kim and J. L. Roebber, J. Chem. Phys., 1966, 44, 1709.
38. J. L. Roebber, J. C. Larrabee and R. E. Huffman, J. Chem. Phys., 1967, 46, 4594.
39. J. L. Roebber, J. Chem. Phys., 1971, 54, 4001.
40. M. Umemoto, H. Shinohara, N. Nishi and R. Shimada, J. Photochem., 1982, 20, 277.
41. J. McFarlane, J. C. Polanyi, J. G. Shapter and J. M. Williamson, J. Photochem. Photobiol., A, 1989, 46, 139.
42. K. H. Becker, R. König, R. Meuser, P. Wiesen and K. D. Bayes, J. Photochem. Photobiol., A, 1992, 64, 1.
43. C. E. M. Strauss, S. H. Kable, G. K. Chawla, P. L. Houston and I. R. Burak, J. Chem. Phys., 1991, 94, 1837.
44. D. D. Davis and W. Braun, Appl. Opt., 1968, 7, 2071.
45. F. C. Fehsenfeld, K. M. Evenson and H. P. Broida, Rev. Sci. Instrum., 1965, 36, 294.
46. W. H. Wing and T. M. Sanders Jr., Rev. Sci. Instrum., 1967, 38, 1341.
47. A. C. G. Mitchell and M. W. Zemansky, Resonance Radiation and Excited Atoms, Cambridge University Press, London, 1961.
48. D. Husain and A. N. Young, J. Chem. Soc., Faraday Trans. 2, 1975, 71, 525.
49. M. W. Zemansky, Phys. Rev., 1929, 34, 313.
50. S. C. Basu and D. Husain, J. Photochem. Photobiol., A, 1988, 42, 1.
51. D. Husain, Faraday Symp. Chem. Soc., 1993, 93, 2165.