CS21B2(1Σ+u)态预离解产物CS的振转布居研究

用一束波长为210.27 nm的激光将CS2分子激发至预离解态1 B2(1 Σ+u),用另一束激光通过激光诱导荧光(LIF)方法检测碎片CS,在250.5～286.5 nm获得了CS碎片A1 Π←X1 Σ+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1 B2(1 Σ+u)态的两个解离通道,即CS(X1 Σ+,v″=0～9)+S(3PJ)和CS(X1 Σ+, v″=0～1)+S(1 B2).由此得到两个解离通道的分支比S(3PJ): S(1 B2)为5.6±1.2.与前人193 nm处的研究结果相比, 210.27 nm激发更有利于S(3PJ)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,为两个Boltzmann分布的合成.

Ro-vibrational Population of CS from CS2 Photodissociation

The rotational and vibrational population of nascent CS(X1Σ+) fragment, produced from dissociation of CS21B2(1Σ+u) at 210.27 nm, were studiedwith laser-induced fluorescence (LIF) spectrum in the wavelength range of 250.5 to 286.5 nm. Itwas found thatthe vibrational population of CS(X1Σ+) consists oftwo parts, correspondingtothe contributions fromtwo dissociation channels, CS(X1Σ+)+S(3PJ) and CS(X1Σ+)+S(1B2). The dissociation channel branching ratio, S(3PJ)/S(1B2), was determined to be 5.6±1.2 from the population. Additionally, the rotational population of some vibrational states (v″= 1, 4~8) of CS(X1Σ+) were obtained fromthe rotationally resolved LIF spectrum, and were found to be non-Boltzmanian.