Palmer Michael H, Ridley Trevor, Hoffmann Søren Vrønning, Jones Nykola C, Coreno Marcello, de Simone Monica, Grazioli Cesare, Biczysko Malgorzata, Baiardi Alberto
School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom.
ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
J Chem Phys. 2015 Apr 7;142(13):134301. doi: 10.1063/1.4916120.
New valence electron photoelectron spectra of iodobenzene obtained using synchrotron radiation have been recorded. Ionization energies (IEs) determined using multi-configuration SCF calculation (MCSCF) procedures confirmed the adiabatic IE order as: X(2)B1<A(2)A2<B(2)B2<C(2)B1. Although it is convenient to retain C2v labelling, there is an evidence that minor distortion to CS symmetry occurs at the MCSCF level for the C state. The fifth ionization process shown to be D(2)A1 exhibits dissociation to C6H5 (+) + I both in the experimental and theoretical studies. The calculated Franck-Condon vibrational spectral envelopes, including hot band contributions, for the first four ionic states reproduce the observed peak positions and intensities with reasonable accuracy. In order to simulate the observed spectra, different bandwidths are required for different states. The increase in the required bandwidths for the A(2)A2 and B(2)B2 states is attributed to internal conversion to lower-lying states. The presence of relatively high intensity sequence bands leads to asymmetry of each of the X(2)B1 state bands.
已记录了使用同步辐射获得的碘苯的新价电子光电子能谱。使用多组态自洽场计算（MCSCF）程序确定的电离能（IEs）证实了绝热IE顺序为：X(2)B1＜A(2)A2＜B(2)B2＜C(2)B1。尽管保留C2v标记很方便，但有证据表明在MCSCF水平上C态会发生向CS对称性的轻微畸变。实验和理论研究均表明，第五电离过程显示为D(2)A1，会解离为C6H5(+) + I。计算得到的前四个离子态的包括热带贡献的弗兰克-康登振动光谱包络，以合理的精度再现了观测到的峰位置和强度。为了模拟观测到的光谱，不同的态需要不同的带宽。A(2)A2和B(2)B2态所需带宽的增加归因于向较低能态的内转换。相对高强度序列带的存在导致X(2)B1态带中的每一个都不对称。
