摘要
用一束波长为 2 10 .2 7nm的激光将CS2 分子激发至预离解态1B2 (1Σ+ u) ,用另一束激光通过激光诱导荧光 (LIF)方法检测碎片CS ,在 2 5 0 .5～ 2 86 .5nm获得了CS碎片A1Π←X1Σ+ 振转分辨的激发谱 .通过对光谱强度的分析 ,获得了CS碎片v″ =0～ 8的振动布居和v″=1,4～ 8振动态的转动布居 .结果发现 ,碎片CS的振动布居呈双模结构 ,分别对应于CS2 分子1B2 (1Σ+ u)态的两个解离通道 ,即CS(X1Σ+ ,v″=0～ 9) +S(3 PJ)和CS(X1Σ+ ,v″ =0～ 1)+S(1B2 ) .由此得到两个解离通道的分支比S(3 PJ) :S(1B2 )为 5 .6± 1.2 .与前人 193nm处的研究结果相比 ,2 10 .2 7nm激发更有利于S(3 PJ)通道的生成 .此外 ,实验还发现CS的转动布居不满足热平衡分布 。
The rotational and vibrational population of nascent CS(X(1)Sigma(+)) fragment, produced from dissociation of (CS2B2)-B-1((1)Sigma(u)(+)) at 210.27 nm, were studied with laser-induced fluorescence (LIF) spectrum in the wavelength range of 250.5 to 286.5 nm. It was found that the vibrational population of CS (X(1)Sigma(+)) consists of two parts, corresponding to the contributions from two dissociation channels, CS (X(1)Sigma(+)) + S (P-3(J)) and CS (X(1)Sigma(+)) + S (B-1(2)). The dissociation channel branching ratio, S (P-3(J))/S (B-1(2)), was determined to be 5.6+/-1.2 from the population. Additionally, the rotational population of some vibrational states (v'=1, 4similar to8) of CS (X(1)Sigma(+)) were obtained from the rotationally resolved LIF spectrum, and were found to be non-Boltzmanian.
基金
ProjectsupportedbytheNationalNaturalScienceFoundationofChina (2 0 2 730 6 3)andtheStateKeyDevelopmentProgramforBasicResearchofChina (19990 75 30 4 )
