Reaction on the O−+CH4 potential energy surface: Dependence on translational and internal energy and on isotopic composition, 93–1313 K
| Autor: | Melani Menedez-Barreto, Robert A. Morris, Thomas M. Miller, A. A. Viggiano, John F. Paulson, R. H. Hobbs, H. Harvey Michels, John A. Montgomery, Jeffrey F. Friedman |
|---|---|
| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | The Journal of Chemical Physics. 106:8455-8463 |
| ISSN: | 1089-7690 0021-9606 |
| Popis: | Rate constants have been measured for the reactions of O− with CH4, CH2D2, and CD4 as a function of ion-neutral average center-of-mass kinetic energy, 〈KEcm〉, at several temperatures over the range 93 K–565 K using a selected ion flow drift tube apparatus. For the CH4 reaction we also report measurements made using a high-temperature flowing afterglow (HTFA) instrument over the temperature range 300 K–1313 K. The rate constants are found to have a very large isotope effect, with the CH4 rate constant a factor of 15 higher than the CD4 rate constant at 93 K. The rate constants generally have a minimum with respect to temperature and 〈KEcm〉, except for the higher-temperature data for CD4 where the rate constants show only an increase with increasing kinetic energy. The data indicate that increasing rotational temperature decreases the rate constants and that rotational energy behaves similarly to translational energy. Single excitations of bending and twisting vibrations have a negligible effect on the rate... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|