Exact quantum 3D cross sections for the Ne+H₂⁺→NeH⁺+H reaction by the hyperspherical method. Comparison with approximate quantum mechanical and classical results

Abstract

Exact, fully converged three-dimensional quantum mechanical cross sections for the title reaction have been computed on the analytical potential energy surface of Pendergast, Heck, Hayes and Jaquet. The close-coupling hyperspherical method of Launay and LeDourneuf has been used for the calculations. Results explicitly shown here correspond to reaction probabilities as a function of total energy and J, integral cross sections and product rotational distributions, for the first three reactant vibrational levels and the ground j=0 reactant rotational level. Integral cross sections confirm the main experimental findings: (a) vibrational excitation greatly enhances reactivity and (b) the reactivity threshold is near the opening of the v=2 reactant channel. Product rotational distributions show an unimodal shape, with its maximum lying at intermediate values of the open product rotational quantum numbers. Results have been compared with previously available centrifugal sudden (CS) and reactive infinite order sudden (R-IOS) results, as well as with quasiclassical trajectory (QCT) calculations. As a general trend, CS and R-IOS integral cross sections show the same qualitative shape as the exact ones, the CS ones being very close to exact but those of R-IOS are between four and five times lower. The QCT results are three times lower and fail to reproduce the threshold behaviour. CS rotational distributions are slightly hotter than exact ones, while QCT results are closer to the exact ones except for the fact that they populate rotational levels not allowed when considering both the zero-point energy and the total energy conservation.

References

1. G. C. Schatz and M. A. Ratner, Quantum Mechanics in Chemistry, Prentice-Hall, Englewood Cliffs, NJ, 1993.
2. J. Chem. Soc., Faraday Trans., 1997, 935, Dynamics of Molecules and Chemical Reactions, ed. R. E. Wyatt and J. Z. H. Zhang, Marcel Dekker, New York, 1996; Advances in Molecular Vibrations and Collision Dynamics, ed. J. M. Bowman, vols. IIA and IIB, JAI Press, Greenwich, CT, 1994.
3. J. M. Launay and M. LeDourneuf, Chem. Phys. Lett., 1989, 163, 178; J. M. Launay, in Dynamical Processes in Molecular Physics, ed. G. Delgado-Barrio, IOP, Bristol, 1993.
4. J. M. Launay and M. LeDourneuf, Chem. Phys. Lett., 1990, 169, 473; J. M. Launay, Theor. Chim. Acta, 1991, 79, 183.
5. P. Honvault and J. M. Launay, Chem. Phys. Lett., 1998, 287, 270.
6. (a) B. Lepetit and J. M. Launay, J. Chem. Phys., 1991, 95, 5159; (b) J. M. Launay and M. LeDourneuf, in Physics of Electronic and Atomic Collisions, Proceedings of the ICPEAC XVII, Brisbane, July 1991, Section 15, IOP Publishing, Bristol, 1992, p. 549.
7. J. M. Launay and S. B. Padkjaer, Chem. Phys. Lett., 1991, 181, 95.
8. S. E. Branchett, S. B. Padkjaer and J. M. Launay, Chem. Phys. Lett., 1993, 208, 523.
9. F. S. Klein and L. Friedman, J. Chem. Phys., 1964, 41, 1789.
10. W. A. Chupka and M. E. Russell, J. Chem. Phys., 1968, 49, 5426.
11. K. R. Ryan and I. G. Graham, J. Chem. Phys., 1973, 59, 4260.
12. D. Van Pijkeren, J. Van Eck and A. Niehaus, Chem. Phys. Lett., 1983, 96, 20.
13. R. M. Bilotta and J. M. Farrar, J. Chem. Phys., 1981, 75, 1776.
14. Z. Herman and I. Koyano, J. Chem. Soc., Faraday Trans. 2, 1987, 83, 127.
15. B. Brunetti, S. Falcinelli, A. Sassara, J. De Andrés and F. Vecchiocattivi, Chem. Phys., 1996, 209, 205.
16. J. B. A. Mitchell, in 1995 Workshop on dissociative recombination: theory, experiments and applications. III, ed. D. Zajfman, J. B. A. Mitchell, D. Schwalm and B. R. Rowe, World Scientific, London, 1995, p. 21.
17. R. D. Mclaughlin and D. L. Thompson, J. Chem. Phys., 1979, 70, 2748.
18. T. Joseph and N. Sathyamurthy, J. Chem. Phys., 1987, 86, 704.
19. A. Aguado and M. Paniagua, J. Chem. Phys., 1992, 96, 1265.
20. J. Urban, R. Jaquet and V. Staemmler, Int. J. Quantum Chem., 1990, 38, 339.
21. J. Urban, L. Klimo, V. Staemmler and R. Jacquet, Z. Phys. D, 1991, 21, 329.
22. P. Pendergast, J. M. Heck, E. F. Hayes and R. Jaquet, J. Chem. Phys. Phys., 1993, 98, 4543.
23. J. D. Kress, Chem. Phys. Lett., 1991, 179, 510.
24. J. D. Kress, J. Chem. Phys., 1992, 95, 8673.
25. J. D. Kress, R. B. Walker, E. F. Hayes and P. Pendergast, J. Chem. Phys., 1994, 100, 2728.
26. M. González, R. M. Blasco, X. Giménez and A. Aguilar, Chem. Phys., 1996, 209, 355.
27. C. Stroud and L. M. Raff, Chem. Phys., 1980, 46, 313.
28. E. F. Hayes, A. K. Q. Siu, F. M. Chapman, Jr. and R. L. Matcha, J. Chem. Phys., 1976, 65, 1901.
29. M. Gilibert, R. M. Blasco, M. González, X. Giménez, A. Aguilar, I. Last and M. Baer, J. Phys. Chem. A, 1997, 101, 6822.
30. B. R. Johnson, J. Comput. Phys., 1973, 13, 445.
31. D. E. Manolopoulos, J. Chem. Phys., 1986, 85, 6425.
32. M. Gilibert, X. Giménez, F. Huarte-Larrañaga, M. González, A. Aguilar, I. Last and M. Baer, J. Chem. Phys., in press.
33. F. J. Aoiz, L. Bañares and V. J. Herrero, J. Chem. Soc., Faraday Trans., 1998, 94, 2483.
34. M. Baer, I. Last and H. J. Loesch, J. Chem. Phys., 1994, 101, 9648 and references therein.
35. G. C. Schatz, in The Theory of Chemical Reaction Dynamics, ed. D. C. Clary, NATO ASI Series C, vol. 170, Reidel, Dordrecht, 1986, p. 1; G. C. Schatz, Chem. Phys. Lett., 1983, 94, 183.
36. H. Szichman, A. J. C. Varandas and M. Baer, J. Chem. Phys., 1995, 102, 3474.
37. X. Giménez, J. M. Lucas, A. Aguilar and A. Laganà, J. Phys. Chem., 1993, 97, 8578.
38. M. Gilibert, X. Giménez, M. González, R. Sayós and A. Aguilar, Chem. Phys., 1995, 191, 1.
39. A. Aguilar, M. Albertí, X. Giménez, X. Grande and A. Laganà, Chem. Phys. Lett., 1995, 223, 201.
40. A. Aguilar, M. Gilibert, X. Giménez, M. González and R. Sayós, J. Chem. Phys., 1995, 103, 4496.
41. A. Laganà, G. Ochoa de Aspuru, A. Aguilar, X. Giménez and J. M. Lucas, J. Phys. Chem., 1995, 99, 11696.
42. See, for instance, Resonances in Electron–Molecule Scattering, van der Waals complexes and Reactive Chemical Dynamics, ed. D. G. Truhlar, American Chemical Society, Washington DC, 1984.
43. M. Gilibert, M. González and R. Sayós, TRIQCT Program, 1992.
44. D. G. Truhlar and J. T. Muckerman, in Atom–Molecule Collision Theory, ed. R. B. Bernstein, Plenum Press, New York, 1981, p. 505, and references therein.
45. M. Ben Nun and R. D. Levine, J. Chem. Phys., 1996, 105, 8136 and references therein.
46. A. González-Ureña, personal communication; D. Bassi, personal communication.
47. G. C. Schatz, D. Sokolovski and J. N. L. Connor, J. Chem. Phys., 1991, 94, 4311.
48. J. M. Bowman, Adv. Chem. Phys., 1985, 61, 115; Q. Sun, J. M. Bowman, G. C. Schatz, J. R. Sharp and J. N. L. Connor, J. Chem. Phys., 1990, 92, 1677.