COLLISIONAL QUENCHING OF ELECTRONICALLY EXCITED ZINC ATOMS - CROSS-SECTIONS AND EXIT CHANNELS

被引:41
作者
BRECKENRIDGE, WH
RENLUND, AM
机构
[1] Department of Chemistry, University of Utah, Salt Lake City
[2] Department of Physical Chemistry, Cambridge University, Cambridge, Lensfield Road
关键词
D O I
10.1021/j100472a008
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Absolute cross sections have been measured for the quenching of excited Zn(1P1) and Zn(3PJ) by several simple molecules. The magnitudes of the cross sections are similar to those determined previously for the analogous Cd(1P1) and Cd(3PJ) states. For Zn(1P1), the cross sections are all large and correlate with the long-range forces C6 parameter to the power 0.9 ± 0.1. Major exit channels for Zn(1P1) vs. Cd(1P1) are dramatically different for several quencher molecules, however. Spin-forbidden collisional production of the 3PJ states, for which branching ratios approach unity in the quenching of Cd(1P1) by N2 and the alkane hydrocarbons, was not detected in the Za(1P1) case for any quencher molecule. Also, metal monohydride production in the quenching by CH4 appears to be a major exit channel for Zn(1P1) but is negligible for the quenching of Cd(1P1) by alkane hydrocarbons. Quenching of Zn(3PJ) occurs with high cross section for the isotopic hydrogens but with only moderate-to-low cross sections for N2, CO, and CH4, similar to earlier results for Cd(3PJ) and Hg(3P1). Possible mechanisms for the quenching of the 1P1 and 3PJ states of Hg, Cd, Zn, and Mg are discussed, such as charge-transfer surface crossings and adiabatic or nonadiabatic chemical reaction pathways via H-M-H or H-M-R potential surfaces (where M is the metal atom and R an alkyl radical). © 1979 American Chemical Society.
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页码:1145 / 1150
页数:6
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