التفاصيل البيبلوغرافية
| العنوان: |
State-selected ion-molecule reactions: Statistical calculations with constraints. |
| المؤلفون: |
Uiterwaal, C. J. G. J., van Eck, J., Niehaus, A. |
| المصدر: |
Journal of Chemical Physics. 5/22/1995, Vol. 102 Issue 20, p7850. 6p. |
| مصطلحات موضوعية: |
*REACTIVITY (Chemistry), *IONS, *NUCLEAR chemistry |
| مستخلص: |
For the two reactive systems, NH3+(Eint)+N H3→NH4++NH2 and H2+(Eint)+H2→H3++H, for which the relative cross sections were measured earlier in our group for Ec.m.≊40 meV we calculated the relative cross section as a function of internal energy using the statistical Rice–Ramsperger–Kassel–Marcus (RRKM) theory that implicitly conserves total energy and total angular momentum. We found satisfactory agreement between theory and experiment by imposing rather mild constraints upon the loose transition state configuration. These constraints involve inactive vibrations and steric hindrance. The steric hindrance imposed in case of the (NH3–NH3)+ system is interpreted as being due to the anisotropic interaction of the ionic charge with the permanent electric dipole of the respective neutral collision partner in the two dissociation channels. We cannot be absolutely sure that the specific combination of modifications we propose for each of the two systems is the only one that agrees well with experiment. However, we find it striking that an agreement can be obtained by such weak and physically meaningful modifications, and we take this as a strong indication that the two studied systems do behave statistical. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR] |
| قاعدة البيانات: |
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