1992 Fiscal Year Final Research Report Summary
Reaction dynamics of excited Zn atoms by off-resonant photoexcitation
| Project/Area Number |
03804028
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
物理化学一般
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
UMEMOTO Hironobu Tokyo Inst. Tech. .App. Phys. .Assistant, 理学部, 助手 (80167288)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Zinc / Intramultiplet Mixing / Intersystem Crossing / Rotational Distribution / Vibrational Distribution / 初期振動状態分布 |
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| Research Abstract |
The dynamical behavior of excited Zn atoms were examined. At the first stage, the intersystem crossing of Zn(4^1P_1) and the intramultiplet mixing of Zn(4^3P_J) by Xe were examined. Effect of the off-resonant photoexcitation was also examined. At the second stage, the chemical reactions of Zn(4^1P_1) with H_2O was examined. The nascent product state distributions were examined.
The interatomic potentials between metal atoms and rare gas atoms have recently been determined by spectroscopic procedures. It is informative to study the dynamics of such systems, because dynamical data complement spectroscopic data in the determination of the potentials, when combined with quantum calculations. The cross sections for the intersystem crossing of Zn(4^1P_1) and the intramultiplet mixing of Zn(4^3P_J) by Xe were determined by using pulsed laser techniques. In the intersystem crossing processes, it was found that the initial J state distribution was skewed to J=2 and that the cross sections were in the order of 10^<-16> cm^2. The cross sections for the intramultiplet mixing were in the order of 10^<-18> cm^2. Quantum mechanical calculations were carried out within a closecoupling treatment to evaluate these cross sections. The above experimental results could well be reproduced by the calculations when suitable potential energy curves were assumed.
In order to understand reaction dynamics, information on the product state distributions are inevitable. The nascent rotational and vibrational state distributions of ZnH and OH in the reaction of Zn(4^1P_1) with H_2O were determined. Since H_2O is corrosive to hot Zn surfaces, a flow system combined with a pulsed nozzle was developed. It was found that OH radicals are very cool, while ZnH radicals are hot, both rotationally and vibrationally. These results suggests that Zn(4^1P_1) abstract H from H^2O via nonlinear intermediates. The reactions with alkane hydrocarbons were also examined.
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