Application of Pulse-Shaping and Multi-Pulse-Train for Control of Chemical Reaction in Condensed Phase and Surface

脉冲整形和多脉冲序列在凝聚相和表面化学反应控制中的应用

基本信息

批准号：
15350009
负责人：
WADA Akihide
金额：
$ 9.47万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15350009/
关键词：
pulse train optimal pulse shaping adaptive control control of excitation efficiency control of reaction coherent control low-frequency vibration mode pulse compression フェムト秒パルス光パルストレイン波形整形パルスシェイピング表面化学超高速分光遠赤外励起

项目摘要

In order to examine the potentiality of multi pulse train and pulse shaping technique for control of chemical reaction, control of excitation process and excited states of perylene crystal was investigated by optimal pulse shaping technique. We succeeded in controlling the emission spectral feature of an α-perylene crystal ; the intensity of E-emission was increased by a factor of 1.4 without the change of Y-emission intensity. Furthermore, we found a near-infrared pulse shape whose multi-photon excitation efficiency is larger than that of a single femtosecond pulse by a factor of two. It was concluded from these results that pulse train and pulse shaping technique can control excitation process of molecules in condensed phase. In order to extend the application area of the pulse-shaping technique by increasing the pulse energy, the compression of femtosecond pulses obtained from a conventional regenerative amplifier was attempted by X^<(2)>:X^<(2)> process using BBO crystals. It was r … More ealized that the pulse width of 120 fs was narrowed to about 80 fs.For the search of the molecular system which can be applied by the pulse shaping technique, the time-resolved experiments were carried out on several molecular-adsorbed-surface systems. It was found on isobutene adsorbed zeolite system that a short-lived species is produced by vibrational excitation of isobutene adsorbed OD groups. From the temporal behavior of OD band intensity, the desorption of isobutene takes places after the vibrational relaxation of OD mode finishes and before the system reaches thermal equilibrium. On the c(4×2)-CO/Ni(111) system, it was found that the site-hopping of CO molecule from hollow site to atop site was induced by the irradiation of intense near-infrared pulses. The hopping phenomenon was found to be entirely transient, with the surface returning to the pre-excited state within a few hundred picoseconds without desorption. The transient response of 10 molecular layers of D_2O ice on CO/Pt(111) at 130 K was also investigated under ultra-high vacuum following a near-infrared pump pulse by sum frequency generation (SFG) spectroscopy. It was revealed that the D_2O molecules in the ice crystalline layer formed an amorphous or liquid-like structure in response to the pumping without desorption of D_2O to the gas phase, and the crystals returned to the crystal structure on a sub-nanosecond time scale. Less

为了检验多脉冲序列和脉冲整形技术控制化学反应的潜力，通过优化脉冲整形技术研究了苝晶体的激发过程和激发态的控制，我们成功地控制了α-的发射光谱特征。苝晶体；在Y发射强度不变的情况下，E发射强度增加了1.4倍，此外，我们发现了多光子激发效率大于单光子激发效率的近红外脉冲形状。从这些结果可以看出，脉冲序列和脉冲整形技术可以控制凝聚相分子的激发过程，从而通过增加脉冲来扩展脉冲整形技术的应用范围。能量，尝试使用 BBO 晶体通过 X^<(2)>:X^<(2)> 过程压缩从传统再生放大器获得的飞秒脉冲。缩小到80 fs左右。为了寻找脉冲整形技术适用的分子体系，对几种分子吸附表面体系进行了时间分辨实验，发现在异丁烯吸附沸石体系上。短寿命物质是由异丁烯吸附的 OD 基团的振动激发产生的。从 OD 带强度的时间行为来看，异丁烯的解吸发生在 OD 基团的振动弛豫之后。 OD模式结束且在系统达到热平衡之前，在c(4×2)-CO/Ni(111)系统上，发现CO分子从空心位点到顶位位点的跳变是由辐照引起的。发现跳跃现象完全是瞬态的，表面在几百皮秒内恢复到预激发状态，而没有解吸。还在超高真空下通过和频发生（SFG）光谱研究了近红外泵浦脉冲后在 130 K 下 CO/Pt(111) 上的 D_2O 冰，结果表明冰晶层中的 D_2O 分子形成了 D_2O 冰。在不将 D_2O 解吸到气相的情况下响应泵浦而形成非晶态或类液体结构，并且晶体在亚纳秒时间尺度上恢复到晶体结构。