作者 | 单位 | E-mail | 刘志明 | 中国科学院武汉物理与数学研究所, 波谱与原子分子物理国家重点实验室, 武汉 430071 | | 王艳梅 | 中国科学院武汉物理与数学研究所, 波谱与原子分子物理国家重点实验室, 武汉 430071 | | 胡春龙 | 中国科学院武汉物理与数学研究所, 波谱与原子分子物理国家重点实验室, 武汉 430071 | | 龙金友 | 中国科学院武汉物理与数学研究所, 波谱与原子分子物理国家重点实验室, 武汉 430071 | | 张冰 | 中国科学院武汉物理与数学研究所, 波谱与原子分子物理国家重点实验室, 武汉 430071 | bzhang@wipm.ac.cn |
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DOI:10.1063/1674-0068/29/cjcp1512243 |
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Photodissociation Dynamics of 2-Iodotoluene Investigated by Femtosecond Time-Resolved Mass Spectrometry |
Zhi-ming Liu,Yan-mei Wang,Chun-long Hu,Jin-you Long,Bing Zhang
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Abstract: |
The photodissociation dynamics of 2-iodotoluene following excitation at 266 nm have been investigated employing femtosecond time-resolved mass spectrometry. The photofragments are detected by multiphoton ionization using an intense laser field centered at 800 nm. A dissociation time of 38±50 fs was measured from the rising time of the co-fragments of toluene radical (C7H7) and iodine atom (I), which is attributed to the averaged time needed for the C-I bond breaking for the simultaneously excited nσ* and ππ* states by 266 nm pump light. In addition, a probe light centered at 298.23 nm corresponding to resonance wavelength of ground-state iodine atom is used to selectively ionize ground-state iodine atoms generated from the dissociation of initially populated nσ* and ππ* states. And a rise time of 40±50 fs is extracted from the fitting of time-dependent I+ transient, which is in agreement with the dissociation time obtained by multiphoton ionization with 800 nm, suggesting that the main dissociative products are ground-state iodine atoms. |
Key words: 2-Iodotoluene Photodissociation Dissociation time Femtosecond time-resolved mass spectrometry |