Matthíasson Kristján, Koumarianou Greta, Jiang Meng-Xu, Glodic Pavle, Samartzis Peter C, Kvaran Ágúst
Science Institute, University of Iceland, Dunhagi 3, 107 Reykjavík, Iceland.
Phys Chem Chem Phys. 2020 Mar 7;22(9):4984-4992. doi: 10.1039/c9cp06242d. Epub 2020 Feb 21.
Mass resolved REMPI spectra, as well as CHand I ion and photoelectron images, were recorded for two-photon resonant excitations of CHI via s, p and d Rydberg states (CHI**) in the excitation region of 55 700 to 70 000 cm. Photoelectron (PE) and ion kinetic energy release spectra (KERs) were derived from the images. The data revealed that after the two-photon resonant excitation, an additional photon is absorbed to form one or more superexcited state(s) (CHI), followed by branching into three pathways. The major one is the dissociation of CHI to form excited Rydberg states of iodine atoms (I**) along with CH(X), a phenomenon not commonly observed in methyl halides. The second (minor) pathway involves autoionization of CHI towards CHI(X), which absorbs another photon to form CH along with I/I* and the third one (minor) is CHI dissociation towards the ion pair, CH + I, prior to I electron ejection. Furthermore, one-photon non-resonant dissociation of CHI to form CH(X) and I/I* prior to three-photon ionization of the fragments is also detected.
记录了质量分辨的共振增强多光子电离（REMPI）光谱，以及CH和I离子与光电子图像，用于在55700至70000厘米的激发区域内通过s、p和d里德堡态（CHI**）对CHI进行双光子共振激发。光电子（PE）和离子动能释放光谱（KERs）由图像得出。数据显示，在双光子共振激发后，额外吸收一个光子形成一个或多个超激发态（CHI），随后分支为三条途径。主要途径是CHI解离形成碘原子的激发里德堡态（I**）以及CH（X），这种现象在卤代甲烷中并不常见。第二条（次要）途径涉及CHI向CHI（X）的自电离，CHI（X）吸收另一个光子形成CH以及I/I*，第三条（次要）途径是在I电子发射之前CHI解离为离子对CH + I。此外，还检测到在碎片的三光子电离之前CHI的单光子非共振解离形成CH（X）和I/I*。
