Dissociative ionization of ethanol by 400 nm femtosecond laser pulses.
Dissociative ionization of ethanol by 400 nm femtosecond laser pulses.
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DOI：
10.1063/1.2387177
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发表时间：
2006-11
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影响因子：
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通讯作者：
H. Yazawa;T. Shioyama;Y. Suda;F. Kannari;R. Itakura;K. Yamanouchi
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文献类型：
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作者：
H. Yazawa;T. Shioyama;Y. Suda;F. Kannari;R. Itakura;K. Yamanouchi
研究了约400纳米短脉冲激光场中乙醇的离解电离。当脉冲时间宽度从60飞秒增加到400飞秒时，C - O键断裂与C - C键断裂的产率比急剧上升，并且在60 - 580飞秒的整个脉宽范围内，该产率比是800纳米处的两到三倍。在400纳米处单电荷乙醇C - O键断裂的增强，以及在10¹² - 10¹³ 瓦/平方厘米相对较弱光场强度下双电荷乙醇库仑爆炸前的键伸长，可通过400纳米较短波长下电子态之间高效的光致耦合来解释。在双脉冲实验中，用一对短脉冲（<80飞秒）照射乙醇，最有效的耦合发生在Δt = 160飞秒，这比800纳米处的Δt = 250飞秒要早得多，其中Δt表示两个脉冲的时间间隔，这表明单电荷乙醇的非绝热场致势交叉在400纳米处比在800纳米处发生得早得多。
The dissociative ionization of ethanol in short-pulsed laser fields at approximately 400 nm is investigated. The yield ratio of the C-O bond breaking with respect to the C-C bond breaking increases sharply as the temporal width increases from 60 to 400 fs, and the yield ratio is two to three times as large as that at 800 nm in the entire pulse-width range of 60-580 fs. The enhancement of the C-O bond breaking of singly charged ethanol at 400 nm and the bond elongation prior to the Coulomb explosion of doubly charged ethanol occurring in the relatively weak light field intensity of 10(12)-10(13) W cm(2) is interpreted by the efficient light-induced coupling among the electronic states at the shorter wavelength of 400 nm. From the double pulse experiment, in which ethanol is irradiated with a pair of short pulses (<80 fs), the most efficient coupling occurs at Deltat=160 fs that is much earlier than Deltat=250 at 800 nm, where Deltat denotes the temporal separation of the two pulses, indicating that the nonadiabatic field-induced potential crossings of singly charged ethanol occurs much earlier at 400 nm than at 800 nm.