Interactions of molecular doubly charged ions with atoms, molecules and photons

Abstract

Gas-phase molecular dipositive ions (molecular dications) are highly unusual and reactive species. The majority of dicationic electronic states rapidly fragment to form a pair of singly charged ions. However, a large number of small molecular dications possess at least one electronic state which is long-lived owing to a barrier in the charge-separating pathway. Such metastable states, which are usually thermodynamically unstable with respect to the charge-separated state, live long enough to allow the study of their interaction with atoms, molecules and photons. It is the results of such experiments that are presented here. Electron-transfer reactions dominate dicationic reactivity with atomic collision partners. The considerable state-selectivity observed in these reactions can be rationalised using a Landau–Zener model of the electron-transfer process. Neutral-loss reactions are also observed following the collisions of polyatomic perfluorinated dications (e.g. SiF₃²⁺) with the rare gases. The form of this neutral-loss reactivity provides a strong clue concerning the structure of these perfluorinated dications. Such deductions are supported by recently performed quantum chemical calculations. With molecular collision partners, bond-forming chemical reactivity is observed. In the case of diatomic neutral molecules, the reactivity appears to involve effective negative ion transfer. Recent isotopic studies are consistent with the conclusion that the prototypical negative ion transfer reaction between CF₂²⁺ and H₂ to give HCF₂⁺, proceeds via a direct mechanism. With simple polyatomic molecules, such as NH₃, recent experiments have shown that molecular dications exhibit complex chemical reactivity. Perfluorinated dications, such as SiF₃²⁺, readily absorb visible laser radiation and subsequently undergo neutral-loss and charge-separating relaxation. These reactions appear consistent with the models of dicationic electronic structure that have been developed to explain the reactions of these perfluorinated dications following collisional excitation.

References

1. M. Larsson, Commun. Atom. Molec. Phys., 1993, 29, 39.
2. D. Mathur, Phys. Rep., 1993, 225, 193.
3. R. Conrad, Physik. Z., 1930, 31, 888.
4. S. Hsieh and J. H. D. Eland, J. Chem. Phys., 1995, 103, 1006.
5. L. H. Andersen, J. H. Posthumus, O. Vahtras, H. Agren, N. Elander, A. Nunez, A. Scrinzi, M. Natiello and M. Larsson, Phys. Rev. Let., 1993, 71, 1812.
6. M. Hochlaf, R. I. Hall, F. Penent, H. Kjeldsen, P. Lablanquie, M. Lavollee and J. H. D. Eland, Chem. Phys., 1996, 207, 159.
7. D. Mathur, L. H. Andersen, P. Hvelplund, D. Kella and C. P. Safvan, J. Phys. B., 1995, 28, 3415.
8. L. E. Dejarme, R. G. Cooks and T. Ast, Org. Mass Spectrom., 1992, 27, 667.
9. P. G. Fournier, J. H. D. Eland, P. Millie, S. Svensson, S. D. Price, J. Fournier, G. Comtet, B. Wannberg, L. Karlsson, P. Baltzer, A. Kaddouri and U. Gelius, J. Chem. Phys., 1988, 89, 3553.
10. S. Leach, J. H. D. Eland and S. D. Price, J. Phys. Chem., 1989, 93, 7575.
11. M. Lundqvist, D. Edvardsson, P. Baltzer, M. Larsson and B. Wannberg, J. Phys. B., 1996, 29, 499.
12. R. I. Hall, L. Avaldi, G. Dawber, A. G. McConkey, M. A. Macdonald and G. C. King, Chem. Phys., 1994, 187, 125.
13. A. S. Mullin, D. M. Szaflarski, K. Yokoyama, G. Gerber and W. C. Lineberger, J. Chem. Phys., 1992, 96, 3636.
14. S. D. Price, Y. Y. Lee, M. Manning and S. R. Leone, Chem. Phys., 1995, 190, 123.
15. J. C. Severs, W. J. Griffiths, F. M. Harris, S. R. Andrews and D. E. Parry, J. Chem. Soc., Faraday Trans., 1996, 92, 3293.
16. F. R. Bennett and I. R. McNab, Chem. Phys. Lett., 1996, 251, 405.
17. P. A. Hatherly, M. Stankiewicz, L. J. Frasinski, K. Codling and M. A. Macdonald, Chem. Phys. Lett., 1989, 159, 355.
18. T. Weiske, W. Koch and H. Schwarz, J. Am. Chem. Soc., 1993, 115, 6312.
19. W. Koch, B. Liu, T. Weiske, C. B. Lebrilla, T. Drewello and H. Schwarz, Chem. Phys. Lett., 1987, 142, 147.
20. Z. Herman, Int. Rev. Phys. Chem., 1996, 15, 299.
21. D. M. Curtis and J. H. D. Eland, Int. J. Mass Spectrom. Ion. Proc., 1985, 63, 241.
22. M. Larsson, P. Baltzer, S. Svensson, B. Wannberg, N. Martensson, A. N. Debrito, N. Correia, M. P. Keane, M. Carlssongothe and L. Karlsson, J. Phys. B, 1990, 23, 1175.
23. R. I. Hall, G. Dawber, A. McConkey, M. A. Macdonald and G. C. King, Phys. Rev. Lett., 1992, 68, 2751.
24. G. Parlant, J. Senekowitsch, S. V. O'Neil and D. R. Yarkony, J. Chem. Phys., 1991, 94, 7208.
25. J. Senekowitsch and S. Oneil, J. Chem. Phys., 1991, 95, 1847.
26. T. D. Mark, in Electron Impact Ionization, ed. T. D. Mark and G. H. Dunn, Springer-Verlag, New York, 1985, p. 137.
27. M. Lundqvist, D. Edvardsson, P. Baltzer and B. Wannberg, J. Phys. B, 1996, 29, 1489.
28. G. Dawber, A. G. McConkey, L. Avaldi, M. A. Macdonald, G. C. King and R. I. Hall, J. Phys. B, 1994, 27, 2191.
29. D. M. Szaflarski, A. S. Mullin, K. Yokoyama, M. N. R. Ashfold and W. C. Lineberger, J. Phys. Chem., 1991, 95, 2122.
30. T. E. Masters and P. J. Sarre, J. Chem. Soc., Faraday Trans., 1990, 86, 2005.
31. J. H. D. Eland, F. S. Wort and R. N. Royds, J. Electron Spectrosc. Relat. Phenom., 1986, 41, 297.
32. J. H. D. Eland, Mol. Phys., 1987, 61, 725.
33. S. Hsieh and J. H. D. Eland, Rapid Commun. Mass Spectrom., 1995, 9, 1261.
34. D. Smith and N. G. Adams, J. Chem. Soc., Faraday Trans., 1989, 85, 1613.
35. D. Smith, Chem. Rev., 1992, 92, 1473.
36. G. Winnewisser and E. Herbst, Rep. Prog. Phys., 1993, 56, 1209.
37. D. Smith and P. Spanel, Mass Spectrom. Rev., 1995, 14, 255.
38. Techniques for the Study of Ion-Molecule Reactions, ed. J. M. Farrar and W. H. Saunders, Techniques of Chemistry, Vol. XX, Wiley, New York, 1988.
39. Z. Herman, P. Jonathan, A. G. Brenton and J. H. Beynon, Chem. Phys. Lett., 1987, 141, 433.
40. C. J. Reid, F. M. Harris and J. H. Beynon, Int. J. Mass Spectrom. Ion. Proc., 1988, 82, 151.
41. C. J. Reid, J. A. Ballantine and F. M. Harris, Int. J. Mass Spectrom. Ion. Proc., 1989, 93, 23.
42. D. Mathur, R. G. Kingston, F. M. Harris, A. G. Brenton and J. H. Beynon, J. Phys. B, 1987, 20, 1811.
43. V. Krishnamurthi, K. Nagesha, V. R. Marathe and D. Mathur, Phys. Rev. A, 1991, 44, 5460.
44. J. M. Curtis and R. K. Boyd, J. Chem. Phys., 1984, 80, 1150.
45. K. Vekey, A. G. Brenton and J. H. Beynon, J. Phys. Chem., 1986, 90, 3569.
46. M. Hamdan and A. G. Brenton, J. Phys. B, 1989, 22, L45.
47. R. Susic, L. Lu, D. E. Riederer, D. Zigon, R. G. Cooks and T. Ast, Org. Mass Spectrom., 1992, 27, 769.
48. A. G. Brenton, J. Mass Spectrom., 1995, 30, 657.
49. S. A. Rogers, S. D. Price and S. R. Leone, J. Chem. Phys., 1993, 98, 280.
50. S. D. Price, S. A. Rogers and S. R. Leone, J. Chem. Phys., 1993, 98, 9455.
51. M. Manning, S. D. Price and S. R. Leone, J. Chem. Phys., 1993, 99, 8695.
52. Y. Y. Lee, S. R. Leone, P. H. Champkin, N. Kaltsoyannis and S. D. Price, J. Chem. Phys., 1997, 106, 7981.
53. Y. Y. Lee and S. R. Leone, J. Phys. Chem., 1995, 99, 15 438.
54. K. Yamasaki and S. R. Leone, J. Chem. Phys., 1989, 90, 964.
55. A. Ehbrecht, N. Mustafa, C. Ottinger and Z. Herman, J. Chem. Phys., 1996, 105, 9833.
56. J. H. Agee, J. B. Wilcox, L. E. Abbey and T. F. Moran, Chem. Phys., 1981, 61, 171.
57. J. O. K. Pedersen and P. Hvelplund, J. Phys. B, 1987, 20, L317.
58. L. Landau, Phys. Z. Sowjetunion, 1932, 2, 26.
59. C. Zener, Proc. R. Soc. London, Ser. A, 1932, 137, 696.
60. E. C. G. Stueckelburg, Helv. Phys. Acta, 1932, 5, 369.
61. Y. U. Demkov, Sov. Phys. JETP, 1964, 18, 138.
62. R. A. Dressler, S. T. Arnold and E. Murad, J. Chem. Phys., 1995, 103, 9989.
63. E. Y. Kamber, K. Akgungor, C. P. Safvan and D. Mathur, Chem. Phys. Lett., 1996, 258, 336.
64. H. R. Koslowski, H. Lebius, V. Staemmler, R. Fink, K. Wiesemann and B. A. Huber, J. Phys. B, 1991, 24, 5023.
65. S. R. Horning, T. Kotiaho, L. E. Dejarme, J. M. Wood and R. G. Cooks, Int. J. Mass Spectrom. Ion. Proc., 1991, 110, 1.
66. M. Farnik, Z. Herman, T. Ruhaltinger and J. P. Toennies, J. Chem. Phys., 1995, 103, 3495.
67. S. D. Price, M. Manning and S. R. Leone, Chem. Phys. Lett., 1993, 214, 553.
68. E. De Hoffmann, J. Chatette and V. Stroobant, Mass Spectrometry, Wiley, Chichester, 1996.
69. N. G. Gotts, P. G. Lethbridge and A. J. Stace, J. Chem. Phys., 1992, 96, 408.
70. M. Lezius and T. D. Mark, Chem. Phys. Lett., 1989, 155, 496.
71. O. Echt, D. Kreisle, E. Recknagel, J. J. Saenz, R. Casero and J. M. Soler, Phys. Rev. A, 1988, 38, 3236.
72. K. Leiter, D. Kreisle, O. Echt and T. D. Mark, J. Phys. Chem., 1987, 91, 2583.
73. P. Scheier, B. Dunser, R. Worgotter, D. Muigg, S. Matt, O. Echt, M. Foltin and T. D. Mark, Phys. Rev. Lett., 1996, 77, 2654.
74. S. D. Price, M. Manning and S. R. Leone, J. Am. Chem. Soc., 1994, 116, 8673.
75. B. K. Chatterjee and R. Johnsen, J. Chem. Phys., 1989, 91, 1378.
76. J. C. Weisshaar, Acc. Chem. Res., 1993, 26, 213.
77. R. Tonkyn and J. C. Weisshaar, J. Am. Chem. Soc., 1986, 108, 7128.
78. L. M. Roth and B. S. Freiser, Mass Spectrom. Rev., 1991, 10, 303.
79. G. Javahery, S. Petrie, H. Wincel, J. Wang and D. K. Bohme, J. Am. Chem. Soc., 1993, 115, 6295.
80. Z. Dolejsek, M. Farnik and Z. Herman, Chem. Phys. Lett., 1995, 235, 99.
81. K. A. Newson and S. Price, Chem. Phys. Lett., 1997, 269, 93.
82. K. Tanaka, T. Kato, P. M. Guyon and I. Koyano, J. Chem. Phys., 1983, 79, 4302.
83. R. A. Dressler, R. H. Salter and E. Murad, J. Chem. Phys., 1993, 99, 1159.
84. J. L. Elkind and P. B. Armentrout, J. Chem. Phys., 1986, 84, 4862.
85. J. P. Maier, J. Electron Spectrosc. Relat. Phenom., 1993, 66, 15.
86. P. A. Martin, F. R. Bennett and J. P. Maier, J. Chem. Phys., 1994, 100, 4766.
87. P. C. Cosby, R. Moller and H. Helm, Phys. Rev. A, 1983, 28, 766.
88. M. Larsson, G. Sundstrom, L. Brostrom and S. Mannervik, J. Chem. Phys., 1992, 97, 1750.
89. G. Sundstrom, M. Carlson, M. Larsson and L. Brostrom, Chem. Phys. Lett., 1994, 218, 17.
90. L. G. M. Pettersson, L. Karlsson, M. P. Keane, A. N. Debrito, N. Correia, M. Larsson, L. Brostrom, S. Mannervik and S. Svensson, J. Chem. Phys., 1992, 96, 4884.
91. J. Senekowitsch, S. V. O'Neil, H. J. Werner and P. J. Knowles, J. Chem. Phys., 1990, 93, 562.
92. I. R. McNab, 1997, personal communication.