title: Dissociative photoionization of isoprene: experiments and calculations.
abstract: Vacuum ultraviolet (VUV) dissociative photoionization of isoprene in the energy region 8.5-18 eV was investigated with photoionization mass spectroscopy (PIMS) using synchrotron radiation (SR). The ionization energy (IE) of isoprene as well as the appearance energies (AEs) of its fragment ions C(5)H(7) (+), C(5)H(5) (+), C(4)H(5) (+), C(3)H(6) (+), C(3)H(5) (+), C(3)H(4) (+), C(3)H(3) (+) and C(2)H(3) (+) were determined with photoionization efficiency (PIE) curves. The dissociation energies of some possible dissociation channels to produce those fragment ions were also determined experimentally. The total energies of C(5)H(8) and its main fragments were calculated using the Gaussian 03 program and the Gaussian-2 method. The IE of C(5)H(8), the AEs for its fragment ions, and the dissociation energies to produce them were predicted using the high-accuracy energy model. According to our results, the experimental dissociation energies were in reasonable agreement with the calculated values of the proposed photodissociation channels of C(5)H(8).
authors.affiliation: Laboratory of Environmental Spectroscopy, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China.
authors.forename: Xianyun
authors.initials: X
authors.lastname: Liu
authors.forename: Weijun
authors.initials: W
authors.lastname: Zhang
authors.forename: Zhenya
authors.initials: Z
authors.lastname: Wang
authors.forename: Mingqiang
authors.initials: M
authors.lastname: Huang
authors.forename: Xibin
authors.initials: X
authors.lastname: Yang
authors.forename: Ling
authors.initials: L
authors.lastname: Tao
authors.forename: Yue
authors.initials: Y
authors.lastname: Sun
authors.forename: Yuntao
authors.initials: Y
authors.lastname: Xu
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Shan
authors.forename: Fuyi
authors.initials: F
authors.lastname: Liu
authors.forename: Liusi
authors.initials: L
authors.lastname: Sheng
mesh_terms: D002070:Butadienes / Q000737:chemistry*; D045782:Hemiterpenes / Q000737:chemistry*; D013058:Mass Spectrometry; D016011:Normal Distribution; D010420:Pentanes / Q000737:chemistry*; D055668:Photochemical Processes; D014466:Ultraviolet Rays
chemical_list: D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; C005059:isoprene