Controlling the femtochemistry of Fe(CO)5
Controlling the femtochemistry of Fe(CO)5
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DOI：
10.1021/jp992541k
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发表时间：
1999-12-09
影响因子：
2.9
通讯作者：
Gerber, G
中科院分区：
文献类型：
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作者：
Bergt, M;Brixner, T;Gerber, G
我们报道了五羰基铁（Fe（CO）（5））在气相中的飞秒光解离和电离反应的主动控制。在脉冲整形器中，采用学习进化算法对飞秒激光脉冲的光谱相位进行修正，根据给定的优化问题，利用实验的直接反馈，迭代地改善激光脉冲的形状。这种多参数优化与单参数控制方案进行了比较，发现它更通用，因为它可以对更一般的搜索空间进行采样。可以从自动优化的结果中提取关于潜在反应机制的信息。它进一步表明，二次谐波产生（SHG）可以用于在输出的800 nm脉冲整形器，以实现400 nm的激发实验。优化过程不仅提高了SHG效率，而且优化了SHG和Fe（CO）（5）光化学组合系统的目标。实验研究的重要性的选择的适应度函数。通过选择适当的加权因子，可以将优化结果从光产物产率的比率的优化调整到绝对光产物产率的优化。演化激光脉冲整形技术被认为是研究光致化学反应过程的一个非常有用的工具。
We report on active control of the femtosecond photodissociation and ionization reactions of iron pentacarbonyl, Fe(CO)(5), in the gas phase. The spectral phase of femtosecond laser pulses is modified in a pulse shaper, employing a learning evolutionary algorithm, Direct feedback from the experiment is used to iteratively improve the laser pulse shape according to a given optimization problem. This many-parameter optimization is compared with one-parameter control schemes and found to be more versatile, because it can sample a much more general search space. Information about the underlying reaction mechanism can be extracted from the results of the automated optimization. It is further shown that second-harmonic generation (SHG) can be used at the output of a 800 nm pulse shaper to implement 400 nm excitation experiments. The optimization procedure not simply increases the SHG efficiency but optimizes the objective given for the combined system of SHG and Fe(CO)(5) photochemistry. The importance of the choice of fitness function is examined experimentally. By choosing appropriate weighting factors, it is possible to tune the optimization results from an optimization of the ratio of photoproduct yields toward optimization of the absolute photoproduct yields. Evolutionary laser pulse shaping is considered a very useful tool for unraveling the processes of photoinduced chemical reactions.