Predissociation dynamics of Ã-state ammonia probed by two-photon excitation spectroscopy
Electronically excited ND 3(A¯) molecules have been prepared by laser two-photon excitation on theA¯ 1A″ 2—X¯ 1′ 1 transition and monitored via their resulting short-lived emission. The earlier observation of Douglas that ND 3(A¯) molecules carrying one quantum of out-of-plane bending vibration ν′ 2...
Saved in:
Published in | Chemical physics Vol. 93; no. 2; pp. 293 - 306 |
---|---|
Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Elsevier B.V
01.02.1985
|
Online Access | Get full text |
Cover
Loading…
Summary: | Electronically excited ND
3(A¯) molecules have been prepared by laser two-photon excitation on theA¯
1A″
2—X¯
1′
1 transition and monitored via their resulting short-lived emission. The earlier observation of Douglas that ND
3(A¯) molecules carrying one quantum of out-of-plane bending vibration ν′
2 are least susceptible to predissociation, is confirmed. ND
3(A¯) predissociation rates are found to be both vibronic and rovibronic level dependent. Both observations may be understood by considering the likely form of the potential energy surface for ND
3(A¯) molecules in the region of the D
2N—D dissociation coordinate. At short D
2N—D separations this surface exhibits a barrier. The presence of a conical intersection (involving the ND
3 ground state surface) further out along the dissociation coordinate has a crucial influence on the magnitude of this barrier. The envisaged form of theA¯-state potential energy surface also provides a qualitative rationale for all previous experimental findings concerning electronic branching ratios and energy disposal amongst the primary photofragments arising in the photodissociation ofA¯-state ammonia. |
---|---|
ISSN: | 0301-0104 |
DOI: | 10.1016/0301-0104(85)80026-4 |