Tunable synchrotron vacuum ultraviolet ionization, time-of-flightinvestigation of the photodissociation of trans-crotonaldehyde at 193nm
Tunable synchrotron vacuum ultraviolet ionization, time-of-flightinvestigation of the photodissociation of trans-crotonaldehyde at 193nm
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DOI：
10.1021/jp049638d
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发表时间：
2004-01
影响因子：
2.9
通讯作者：
J. Shu;D. Peterka;S. Leone;Musahid Ahmed
中科院分区：
文献类型：
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作者：
J. Shu;D. Peterka;S. Leone;Musahid Ahmed
利用光碎片平移谱（PTS）研究了不饱和反式巴豆醛（CH 3CHCHCHO）分子在193 nm处的光解离，并用可调谐同步辐射紫外电离进行了探测.在分子量为68（C4 H4 O +），55（C3 H3 O +），41（C3 H5+），40（C3 H4+），39（C3 H3+），29（？）测定了28（CO +）、27（C2 H3+）、26（C2 H2+）和15（CH 3 +）。第29章无法确定对实验结果的分析揭示了三种解离通道：H + C4 H5 O，CH 3 + C3 H3 O和CO + C3 H6.与质量29相关的第四个通道可以反映HCO或C2 H5的形成。测量还表明C3 H6发生了强烈的二次解离.通过拟合碎片的TOF质谱得到的质心（CM）平移能分布分别为H + C4 H5 O、CH 3 + C3 H3 O和CO + C3 H6通道的平均CM动能值42、23和43 kJ/mol。首次测量了CHCHCHO自由基的光电离产额曲线，起始电子伏特≤ 7.6eV。将巴豆醛的光解机理与丙烯醛（CH 2CHCHO）的光解动力学进行了比较.
Photodissociation of the unsaturated trans-crotonaldehyde (CH 3 CHCHCHO) molecule at 193 nm is studied using photofragment translational spectroscopy (PTS) and detected by ionization with tunable synchrotron ultraviolet radiation. The photofragment time-of-flight (TOF) spectra at mle = 68(C 4 H 4 O + ), 55(C 3 H 3 O + ), 41(C 3 H 5 + ), 40(C 3 H 4 + ), 39(C 3 H 3 + ), 29(?), 28(CO + ), 27(C 2 H 3 + ), 26(C 2 H 2 + ), and 15(CH 3 + ) are measured. Mass 29 could not be unambiguously assigned. Analysis of these experimental results reveals three dissociation channels: H + C 4 H 5 O, CH 3 + C 3 H 3 O, and CO + C 3 H 6 . A fourth channel associated with mass 29 could reflect either formation of HCO or C 2 H 5 . The measurements also indicate that C 3 H 6 undergoes strong secondary dissociation. The center of mass (CM) translational energy distributions obtained by fitting the TOF mass spectra of the fragments yield values 42, 23, and 43 kJ/mol average CM kinetic energies for the H + C 4 H 5 O, CH 3 + C 3 H 3 O and CO + C 3 H 6 channels, respectively. The photoionization yield curve of the CHCHCHO radical is measured for the first time with an onset ≤7.6 eV. The photodissociation mechanism of crotonaldehyde is compared with the photodissociation dynamics of acrolein (CH 2 CHCHO).