School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK.
Phys Chem Chem Phys. 2014 Jan 14;16(2):430-43. doi: 10.1039/c3cp53055h.
The intramolecular vibrational redistribution (IVR) dynamics following the excitation of a mode in the first electronically excited states of toluene, toluene-d3 and p-fluorotoluene that has predominantly C-CH3 stretching character and an internal energy of ~1200 cm(-1) have been compared using picosecond time-resolved photoelectron imaging spectroscopy as a probe. Temporal changes in the intensities of spectral features in each molecule have enabled IVR lifetimes of 12, 15 and 50 ps, respectively, to be determined. Our measurements show that doorway states are critical in mediating the IVR dynamics in toluene and toluene-d3, and we deduce that these doorway states, which are assigned in the course of this work, are also instrumental in reducing the IVR lifetimes of these molecules relative to p-fluorotoluene.
采用皮秒时间分辨光电子成像光谱学作为探针，比较了甲苯、氘代甲苯和对氟甲苯在第一电子激发态中激发一个主要具有 C-CH3 伸缩特征且内部能量约为 1200cm-1 的模式后，分子内振动再分配（IVR）动力学。通过比较各分子中光谱特征强度的时间变化，分别确定了 12、15 和 50 ps 的 IVR 寿命。我们的测量结果表明，在甲苯和氘代甲苯中，门控态在介导 IVR 动力学中起着关键作用，我们推断，在这项工作中分配的这些门控态对于降低这些分子相对于对氟甲苯的 IVR 寿命也起着重要作用。
