School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
J Chem Phys. 2017 Jun 28;146(24):244310. doi: 10.1063/1.4986862.
A study of the vibration and vibration-torsion levels of para-fluorotoluene in the 580-830 cm region is presented, where a number of features are located whose identity is complicated by interactions and overlap. We examine this region with a view to ascertaining the assignments of the bands; in particular, identifying those that arise from interactions involving various zero-order states (ZOSs) involving both vibrations and torsions. Resonance-enhanced multiphoton ionization (REMPI) is employed to identify the wavenumbers of the relevant transitions, and subsequently zero-kinetic-energy (ZEKE) spectra are recorded to assign the various eigenstates. In some cases, a set of ZEKE spectra are recorded across the wavenumber range of a REMPI feature, and we construct what we term a two-dimensional ZEKE (2D-ZEKE) spectrum, which allows the changing ZOS contributions to the eigenstates to be ascertained. Assignment of the observed bands is aided by quantum chemical calculations and all b and a symmetry vibrational wavenumbers are now determined in the S state and cation, as well as those of the D vibration. We also compare to the activity seen in the corresponding S ← S spectrum of para-difluorobenzene.
研究了在 580-830cm 区域内对氟甲苯的振动和振动-扭转水平，其中存在许多特征，其身份由于相互作用和重叠而变得复杂。我们检查了这一区域，以期确定带的分配；特别是确定那些源自涉及各种零阶态（ZOS）的相互作用的那些，这些 ZOS 涉及振动和扭转。共振增强多光子电离（REMPI）用于识别相关跃迁的波数，随后记录零动能（ZEKE）谱以分配各种本征态。在某些情况下， across across 在 REMPI 特征的波数范围内记录了一组 ZEKE 光谱，我们构建了我们所谓的二维 ZEKE（2D-ZEKE）光谱，这允许确定本征态中不断变化的 ZOS 贡献。通过量子化学计算来辅助观察带的分配，现在确定了 S 态和阳离子以及 D 振动的所有 b 和 a 对称振动波数。我们还与对氟苯相应的 S ← S 光谱中的活性进行了比较。
