European journal of mass spectrometry (Chichester, England)

1469-06672062014European journal of mass spectrometry (Chichester, England)Eur J Mass Spectrom (Chichester)Dissociative photoionization of β-pinene: an experimental and theoretical study.419428419-2810.1255/ejms.1304We investigated the photoionization and dissociation photoionization of the β-pinene molecular using time-of-flight mass spectrometry with a tunable vacuum ultraviolet source in the region from 8.00eV to 15.50eV. The experimental ionization energy (IE) value is 8.60eV using electron impact as the ionization source which is not in good agreement with theoretical value (8.41 eV) with a G3MP2 method. We obtained the accurate IE of β-pinene (8.45 ± 0.03eV) derived from the efficiency spectrum which is in good agreement with the theoretical value (8.38eV) of the CBS-QB3 method. We elucidated the dissociation pathways of primary fragment ions from the β-pinene cation on the basis of experimental observations in combination with theoretical calculations. Most of the dissociation pathways occur via a rearrangement reaction prior to dissociation. We also determined the structures of the transition states and intermediates for those isomerization processes.ShengLiusiLNational Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China Hefei 230029, China.. lssheng@ustc.edu.cn.CaoMaoqiMNational Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China Hefei 230029, China. caomaoqi@mail.ustc.edu.cn.ChenJunJNational Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China Hefei 230029, China.. jchenah@mail.ustc.edu.cn.FangWenzhenWNational Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China Hefei 230029, China. Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China. fangwz@mail.ustl.edu.cn.LiYuquanYNational Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China Hefei 230029, China. yquan@mail.ustl.edu.cn.GeShaolinSNational Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China Hefei 230029, China. slge@mail.ustc.edu.cn.ShanXiaobinXNational Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China Hefei 230029, China. shanxb@ustc.edu.cn.LiuFuyiFNational Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China Hefei 230029, China. fyliu@ustc.edu.cn.ZhaoYujieYNational Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China Hefei 230029, China. School of Nuclear Engineering and Geophysics, East China Institute of Technology, Nanchang, Jiangxi 330013, China. jackzyj@ustc.edu.cn.Zhenya WangZhenya WangZWLaboratory of Environmental Spectroscopy, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China. zyw@aiofm.ac.cn.engJournal Article