丁酮3s里德堡态的超快光解动力学研究
发布时间：2018-07-25 06:32
【摘要】：本文采用195.8 nm飞秒激光将丁酮分子激发到S_2(n,3s)里德堡态,在800 nm探测光的作用下获得时间分辨的飞行时间质谱.对实验结果的分析表明,由于丁酮α位置具有一个甲基和一个乙基,使得NorrishⅠ型解离反应表现出丰富的动力学特征.母体离子瞬态衰减的时间常数为(2.23±0.02)ps.丙酰基离子瞬态衰减与母体类似,只有一个为(2.15±0.02)ps的时间常数,说明丙酰基离子来自于母体的解离性电离.乙酰基离子的时间曲线拟合得到四个时间常数:τ_1=(2.40±0.15)ps,τ_2=(1.10±0.25)ps,τ_3=(0.08±0.02)ps,τ_4=(17.72±0.80)ps,分别对应于S_2→S_1的内转换,S_1态生成CH_3CO(A)的初步解离,CH_3CO(A)快速内转换为CH_3CO(X),以及CH_3CO(X)基态上的二次解离.丁酮分子α-C-C键的解离存在分子内振动能量再分配(IVR)与势垒解离两种竞争的解离通道,但在该实验条件下,我们认为是通过分子内振动能量再分配通道发生解离的结果.
[Abstract]:In this paper, a 195.8 nm femtosecond laser is used to excite the butanone molecule to the S _ S _ 2 (n ~ 3s) Rydberg state. The time-resolved time-of-flight mass spectrometry is obtained under the action of 800nm probe light. The analysis of the experimental results shows that the dissociation reaction of Norrish type I exhibits rich kinetic characteristics due to the presence of one methyl and one ethyl in the 伪 position of butanone. The time constant of the transient decay of the parent ion is (2.23 卤0.02) PS. The transient decay of propionyl ions is similar to that of the parent, with only one time constant of (2.15 卤0.02) PS, which indicates that the propionyl ion comes from the dissociation ionization of the parent. Four time constants were obtained by fitting the time curve of acetyl ions: 蟿 _ 1 = (2.40 卤0.15) pss, 蟿 _ s _ 2 = (1.10 卤0.25) pss, 蟿 _ 3 = (0.08 卤0.02) pss, 蟿 _ 4 = (17.72 卤0.80) pss, respectively, corresponding to the initial dissociation of S _ 2 / S _ 2 / S _ (1) and the initial dissociation of Ch _ 3CO (A) to CH_3CO (X), and the second dissociation of CH_3CO (X) in ground state. The dissociation of the 伪 -C-C bond of butanone molecule has two competitive dissociation channels: intramolecular vibrational energy redistribution (IVR) and barrier dissociation. However, under these experimental conditions, we believe that the dissociation results occur through the intramolecular vibrational energy redistribution channel.
【作者单位】： 昆明学院物理科学与技术系;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;
【基金】：国家重点基础研究发展计划(批准号:2013CB922200) 国家自然科学基金(批准号:21573279,21273274)资助的课题~~
【分类号】：O623.521
，
本文编号：2142940
[Abstract]:In this paper, a 195.8 nm femtosecond laser is used to excite the butanone molecule to the S _ S _ 2 (n ~ 3s) Rydberg state. The time-resolved time-of-flight mass spectrometry is obtained under the action of 800nm probe light. The analysis of the experimental results shows that the dissociation reaction of Norrish type I exhibits rich kinetic characteristics due to the presence of one methyl and one ethyl in the 伪 position of butanone. The time constant of the transient decay of the parent ion is (2.23 卤0.02) PS. The transient decay of propionyl ions is similar to that of the parent, with only one time constant of (2.15 卤0.02) PS, which indicates that the propionyl ion comes from the dissociation ionization of the parent. Four time constants were obtained by fitting the time curve of acetyl ions: 蟿 _ 1 = (2.40 卤0.15) pss, 蟿 _ s _ 2 = (1.10 卤0.25) pss, 蟿 _ 3 = (0.08 卤0.02) pss, 蟿 _ 4 = (17.72 卤0.80) pss, respectively, corresponding to the initial dissociation of S _ 2 / S _ 2 / S _ (1) and the initial dissociation of Ch _ 3CO (A) to CH_3CO (X), and the second dissociation of CH_3CO (X) in ground state. The dissociation of the 伪 -C-C bond of butanone molecule has two competitive dissociation channels: intramolecular vibrational energy redistribution (IVR) and barrier dissociation. However, under these experimental conditions, we believe that the dissociation results occur through the intramolecular vibrational energy redistribution channel.
【作者单位】： 昆明学院物理科学与技术系;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;
【基金】：国家重点基础研究发展计划(批准号:2013CB922200) 国家自然科学基金(批准号:21573279,21273274)资助的课题~~
【分类号】：O623.521
，
本文编号：2142940
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