Control of bond-selective photochemistry in CH2BrCl using adaptive femtosecond pulse shaping
Control of bond-selective photochemistry in CH2BrCl using adaptive femtosecond pulse shaping
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DOI：
10.1140/epjd/e2002-00101-8
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发表时间：
2002-07-01
影响因子：
1.8
通讯作者：
Gerber, G
中科院分区：
文献类型：
--
作者：
Damrauer, NH;Dietl, C;Gerber, G
采用自适应飞秒激光脉冲整形来实现气相中 CH2ClBr 的键选择性光解离/光电离。在反射器飞行时间质谱仪中测量的光产物信号用作反馈，通过进化算法迭代地改进激光脉冲的光谱相位。我们观察到较强碳卤键与较弱碳卤键的裂变增加了 100%。事实证明单参数控制方案无法实现键选择性。通过将控制问题映射到众所周知的最大化二次谐波生成 (SHG) 问题来解决控制问题的复杂性。进一步的光谱结果表明，控制涉及中性表面上波包动力学的操纵。
Adaptive femtosecond laser pulse shaping is employed to achieve bond selective photodissociation/photoionization of CH2ClBr in the gas phase. The photoproduct signal measured in a reflectron time-of-flight mass spectrometer is used as feedback to improve iteratively the spectral phases of the laser pulse via an evolutionary algorithm. We observe an increase of the fission of the stronger versus the weaker carbon halogen bond by 100%. Single parameter control schemes proved unable to achieve bond-selectivity. The complexity of the control problem is addressed by mapping it onto the well-known problem of maximizing second-harmonic generation (SHG). Further spectroscopic results indicate that the control involves manipulation of wave-packet dynamics on the neutral surfaces.