Gans Bérenger, Lamarre Nicolas, Broquier Michel, Liévin Jacques, Boyé-Péronne Séverine
Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS UMR 8214, University of Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France.
Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles, CP 160/09, B-1050 Bruxelles, Belgium.
J Chem Phys. 2016 Dec 21;145(23):234309. doi: 10.1063/1.4972018.
Vacuum-ultraviolet pulsed-field-ionization zero-kinetic-energy photoelectron spectra of XΠ2←XΣ+1 and BΠ2←XΣ+1 transitions of the HCN and HCN isotopologues of cyanoacetylene have been recorded. The resolution of the photoelectron spectra allowed us to resolve the vibrational structures and the spin-orbit splittings in the cation. Accurate values of the adiabatic ionization potentials of the two isotopologues (E/hc(HCN)=93 909(2) cm and E/hc(HCN)=93 912(2) cm), the vibrational frequencies of the ν, ν, and ν vibrational modes, and the spin-orbit coupling constant (A = -44(2) cm) of the XΠ2 cationic ground state have been derived from the measurements. Using ab initio calculations, the unexpected structure of the BΠ2←XΣ+1 transition is tentatively attributed to a conical intersection between the A and B electronic states of the cation.
已记录了氰基乙炔的HCN及其同位素变体的XΠ2←XΣ+1和BΠ2←XΣ+1跃迁的真空紫外脉冲场电离零动能光电子能谱。光电子能谱的分辨率使我们能够分辨出阳离子中的振动结构和自旋轨道分裂。从测量中得出了两种同位素变体的绝热电离能的精确值（E/hc(HCN)=93 909(2) cm和E/hc(HCN)=93 912(2) cm）、ν、ν和ν振动模式的振动频率以及XΠ2阳离子基态的自旋轨道耦合常数（A = -44(2) cm）。使用从头算计算，BΠ2←XΣ+1跃迁的意外结构初步归因于阳离子的A和B电子态之间的锥形交叉。
