Department of Chemistry, National Taiwan University, Taipei 106, Taiwan.
J Phys Chem A. 2010 Jul 15;114(27):7275-83. doi: 10.1021/jp1030653.
In one-photon dissociation of gaseous acetyl chloride at 248 nm, time-resolved Fourier-transform infrared emission spectroscopy is used to detect the fragments of HCl, CO, and CH(2) in the presence of Ar or O(2). The high-resolution spectra of HCl and CO are analyzed to yield the corresponding internal energy deposition of 8.9 +/- 1.1 and 6.2 +/- 0.9 kcal/mol. The presence of the CH(2) fragment is verified by detecting the CO(2) product resulting from the reaction of CH(2) and the added O(2). The probability of the HCl formation via a hot Cl reaction with the precursor is examined to be negligible by performing two experiments, the CH(3)COCl pressure dependence and the measurement of Br(2) with Cl reaction. The HCl elimination channel under the Ar addition is verified to be slowed by 2 orders of magnitude, as compared to the Cl elimination channel. The observed fragments are proposed to dissociate on the hot ground electronic state via collision-induced internal conversion. A two-body dissociation channel is favored leading to HCl and CH(2)CO, followed by secondary dissociation.
在 248nm 下气态乙酰氯的单光子离解中，采用时间分辨傅里叶变换红外发射光谱法在存在 Ar 或 O2 的情况下检测 HCl、CO 和 CH(2)的碎片。分析 HCl 和 CO 的高分辨率光谱，得出相应的内部能量沉积分别为 8.9±1.1 和 6.2±0.9kcal/mol。通过检测由 CH(2)和添加的 O(2)反应生成的 CO(2)产物，验证了 CH(2)碎片的存在。通过进行两个实验，即 CH(3)COCl 压力依赖性和 Cl 与 Br(2)的反应测量，检查了通过热 Cl 反应与前体形成 HCl 的可能性，结果表明这种可能性可以忽略不计。在添加 Ar 的情况下，HCl 消除通道的速度比 Cl 消除通道慢 2 个数量级。所观察到的碎片被提出通过碰撞诱导的内部转换在热基态电子态上解离。优先选择二体解离通道，生成 HCl 和 CH(2)CO，然后进行次级解离。
