ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Using a pump–probe method, we have systematically studied the rotational distribution of KH (v=0–3) produced in the reaction of K (5P, 6P, and 7P) with H2. The resulting rotational states fit roughly a statistical distribution at the system temperature, while the vibrational populations are characterized by a Boltzmann vibrational temperature of 1800, 3000, and 3100 K for the 5p, 6P, and 7P states, respectively. These results provide evidence that the reaction follows a collinear collisional geometry. This work has successfully probed KH from the K(5P) reaction, and confirms that a nonadiabatical transition via formation of an ion-pair K+H−2 intermediate should account for the reaction pathway. The available energy dissipation was measured to be (68±4)%, (26±2)%, and (6±3)% into the translation, vibration, and rotation of the KH product, respectively. The energy conversion into vibrational degree of freedom generally increases with the principal quantum number, indicating that the electron-jump distance elongates along the order of 5P〈6P〈7P. The result is different from the Cs(8P,9P)–H2 case, in which the electron-jump distances were considered roughly the same. Furthermore, a relatively large distance is expected to account for highly vibrational excitation found in the KH product. According to the classical trajectory computation reported by Polanyi and co-workers, the strong instability of the H−2 bond, inducing a large repulsion energy, appears to favor energy partitioning into the translation. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.472746
Permalink
