Department of Physics and Astronomy, Queen's University, Belfast BT7 1NN, UK.
J Phys Chem A. 2010 Jan 28;114(3):1474-84. doi: 10.1021/jp9081992.
Results from a joint experimental study of electron attachment to dichlorodifluoromethane (CCl(2)F(2)) molecules in the gas phase are reported. In a high resolution electron beam experiment involving two versions of the laser photoelectron attachment method, the relative cross section for formation of the dominant anion Cl(-) was measured over the energy range 0.001-1.8 eV at the gas temperature T(G) = 300 K. It exhibits cusp structure at thresholds for vibrational excitation of the nu(3)(a(1)) mode due to interaction with the attachment channels. With reference to the thermal attachment rate coefficient k(T = 300 K) = 2.2(8) x 10(-9) cm(3) s(-1) (fitted average from several data), a new highly resolved absolute attachment cross section for T(G) = 300 K was determined. Partial cross sections for formation of the anions Cl(-), Cl(2)(-), F(-), ClF(-), and CCl(2)F(-) were measured over the range 0-12 eV, using three different electron beam experiments of medium energy resolution. The dependence of the attachment rate coefficient k(T(e);T(G) = 300 K) on electron temperature T(e) was calculated over the range 50-15 000 K, based on a newly constructed total cross section for anion formation at T(G) = 300 K. R-matrix calculations for Cl(-) production have been carried out for comparison with the experimental data. The R-matrix results are in line with the main experimental observations and predict the dependence of the DEA cross section on the initial vibrational level nu(3)() and on the vibrational temperature. Furthermore, the cross section for vibrational excitation of the nu(3) mode has been computed.
报告了气相中二氯二氟甲烷（CCl2F2）分子电子附加的联合实验研究结果。在涉及两种激光光电子附加方法的高分辨率电子束实验中，在气体温度 T(G) = 300 K 下，在 0.001-1.8 eV 的能量范围内测量了形成主要阴离子 Cl-的相对横截面。由于与附加通道的相互作用，在振动激发 nu(3)(a(1))模式的阈值处出现了尖峰结构。参照热附着速率系数 k(T = 300 K) = 2.2(8) x 10-9 cm3 s-1（从几个数据拟合的平均值），确定了新的高度分辨率的绝对附着横截面 T(G) = 300 K。使用三种不同的中等能量分辨率的电子束实验，在 0-12 eV 的范围内测量了形成阴离子 Cl-、Cl2-、F-、ClF-和 CCl2F-的部分横截面。基于在 T(G) = 300 K 下构建的新的阴离子形成总横截面，计算了附着速率系数 k(T(e);T(G) = 300 K)对电子温度 T(e)的依赖性，范围为 50-15000 K。已经进行了 Cl-生成的 R 矩阵计算，以便与实验数据进行比较。R 矩阵结果与主要实验观察结果一致，并预测了 DEA 横截面对初始振动能级 nu(3)()和振动温度的依赖性。此外，还计算了 nu(3)模式振动激发的横截面。
