K(6S)+H2→KH+H转动分辨反应截面的测量

摘要

Using pump-probe method and optical absorption technique,we have measured the nascent quantum state distributions of the KH product and the cross sections for reaction of K(6S) with H2.The K(6S) state was excited with a pulsed laser by two-photon absorption.The nascent rotational distributions of KH(v=0,1) were determined from laserinduced fluorescence spectrum.The rotational population profiles were roughly consistent with a statistical distribution at the cell temperature.The densities of K(6S) atoms were evaluated directly from the pump laser energy loss which was absorbed by K atoms.The densities of KH molecules were measured by monitoring the absorption of a counter-propagating probe laser beam,tuned to X1∑+-A1∑+ transitions.Using a rate equation model,we obtained rotationally resolved reaction cross sections.The total cross sections obtained by summing the individual rotationally resolved cross sections are σ(v =0) =(1.3 + 0.5) × 10-16cm2 and σ(v =1) =(0.05 + 0.02) × 10-16cm2,respectively.%利用泵浦-检测技术和光学吸收技术,对K(6S)与H2反应生成的初生态产物KH(X1∑+,v=0,1)的转动态分布和反应截面作了测量.脉冲激光双光子激发K原子至K(6S)态,通过泵浦-探测技术确定了KH(X1∑+,v=0,1)初生态的转动分布,转动分布接近样品池温时的统计分布.通过测量泵浦激光的能量损失确定K(6S)态原子密度,测量检测激光的吸收系数得到反应产物KH分子的密度,由速率方程分析可以得到转动分辨的反应截面,总的反应截面为所有转动分辨的反应截面之和,得到的反应截面分别为(1.3+0.5)× 10-16cm2(对v=0)和(0.05±0.02)×10-16cm2(对v=1).