Dissociative photoionization of isoprene: experiments and calculations.
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).
Liu
Xianyun
X
Laboratory of Environmental Spectroscopy, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China.
Zhang
Weijun
W
Wang
Zhenya
Z
Huang
Mingqiang
M
Yang
Xibin
X
Tao
Ling
L
Sun
Yue
Y
Xu
Yuntao
Y
Shan
Xiaobin
X
Liu
Fuyi
F
Sheng
Liusi
L
D002070:Butadienes / Q000737:chemistry*; D045782:Hemiterpenes / Q000737:chemistry*; D013058:Mass Spectrometry; D016011:Normal Distribution; D010420:Pentanes / Q000737:chemistry*; D055668:Photochemical Processes; D014466:Ultraviolet Rays
D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; C005059:isoprene