Combined experimental and theoretical study on photoionization cross sections of benzonitrile and o / m / p -cyanotoluene

The Journal of Chemical Physics, vol. 154, pp. 244301

Abstract

Photoionization cross sections (PICSs) for the products of the reaction from CN with toluene, including benzonitrile and o/m/p-cyanotoluene, were obtained at photon energies ranging from ionization thresholds to 14 eV by tunable synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). Theoretical calculations based on the frozen-core Hartree-Fock approximation and Franck-Condon simulations were carried out to cross-verify the measured PICS. The results show that the photoionization cross sections of benzonitrile and cyanotoluene isomers are similar. The generalized charge decomposition analysis was used to investigate the components of the highest occupied molecular orbital (HOMO) and HOMO-1. It was found that the HOMO and HOMO-1 of benzonitrile and cyanotoluene isomers are dominated by the features of the benzene ring, indicating that the substitution of CN and methyl has a minor influence on the PICS of the studied molecules. The reported PICS on benzonitrile and cyanotoluene isomers in the present work could contribute to the near-threshold PIMS experiments and determine the ionization and dissociation rates in interstellar space for these crucial species. The theoretical analysis on characteristics of molecular orbitals provides clues to estimating the PICS of similar substituted aromatic compounds.

Authors 7

1. Jiabin Huang

   University of Science and Technology of China

   Affiliation as printed

   Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China 1 , Hefei, Anhui 230026, People’s Republic of China

2. Can Huang Aachen Chair of Technical Thermodynamics

   RWTH Aachen University

   Affiliation as printed

   Chair of Technical Thermodynamics, RWTH Aachen University 2 , 52062 Aachen, Germany

3. Xiaoqing Wu

   University of Science and Technology of China · National Synchrotron Radiation Laboratory

   Affiliation as printed

   Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China 1 , Hefei, Anhui 230026, People’s Republic of China

   National Synchrotron Radiation Laboratory, University of Science and Technology of China 3 , Hefei, Anhui 230029, People’s Republic of China

4. Qifeng Hou

   University of Science and Technology of China

   Affiliation as printed

   Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China 1 , Hefei, Anhui 230026, People’s Republic of China

5. Guangjun Tian

   Yanshan University

   Affiliation as printed

   Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University 4 , Qinhuangdao 066004, People’s Republic of China

6. Jiuzhong Yang corresponding

   University of Science and Technology of China · National Synchrotron Radiation Laboratory

   Affiliation as printed

   National Synchrotron Radiation Laboratory, University of Science and Technology of China 3 , Hefei, Anhui 230029, People’s Republic of China

7. Feng P. Zhang corresponding

   University of Science and Technology of China

   Affiliation as printed

   Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China 1 , Hefei, Anhui 230026, People’s Republic of China