TY - JOUR T1 - Study on $H_3^+$ Formation by Synchrotron Radiation AU - Zhang , Qiang AU - Cao , Maoqi AU - Shan , Xiaobin AU - Li , Yuquan AU - Wang , Zhenya AU - Sheng , Liusi JO - Journal of Atomic and Molecular Sciences VL - 2 SP - 148 EP - 155 PY - 2014 DA - 2014/05 SN - 5 DO - http://doi.org/10.4208/jams.042813.070213a UR - https://global-sci.org/intro/article_detail/jams/8319.html KW - $H^+_3$, photoionization, synchrotron radiation, ab initio calculation. AB -

A molecular beam experiment on the formation of $H^+_3$ has been carried out by using tunable vacuum ultraviolet (VUV) synchrotron radiation. Reflectron time-of-flight mass spectrometer is applied to detect the signal of $H^+_3.$ The ionization energy (IE) of $H_2$ and the appearance energy (AE) of $H^+_3$ are determined to be 15.41 eV and 14.61 eV, respectively, by measurements of photoionization efficiency (PIE) curves. Additionally, two most likely $H^+_3$ formation ways, $(H_2)2\rightarrow H^3_+  +H$ and $(H_2)_3 \rightarrow H^+_3 +H+H_2,$ are discussed by ab initio calculations at CCSD(T) and MP2 level with aug-cc-pVQZ basis set and compared with the experimental result. The optimized geometries of species involved in the dissociative photoionization channels are also determined at MP2/aug-cc-pVQZ level.