International Collaboration in Chemistry: Control of Ultrafast EUV-induced Chemical Reactions

我们将研究超短延时EUV/IR光场对分子离子形成和碎裂的控制。使用超快激光脉冲来实时跟踪并最终控制分子在激发后重新排列的反应路径是当今化学和物理学中一个常见且大量研究的主题。最近的一个发展是通过高次谐波产生在10-100 eV范围内产生高能光子，具有足够的通量，它们可以用作束流来激发/电离宏观样品气体的可工作部分。这样的光子具有足够的能量来激发和电离分子。双电荷分子离子通常分解成带电碎片，综合动量成像技术(如COLTRIMS、反应显微镜、TRCIS等1)可用于测量所有带电反应产物的全动量矢量，包括离子和电子。在超短极紫外光脉冲激发离子分子产生脉冲后，可以用第二个强红外脉冲控制碎裂路径，其强度、波形和时间是控制参数。我们建议通过结合一个机构(KSU)的动量成像专业知识和另一个机构(MPQ)的高次谐波生成专业知识来研究这种过程。

We will investigate the control of the formation and fragmentation of molecular ions by ultrashort time delayed EUV/IR light fields. The use of ultrafast laser pulses to follow in real time, and ultimately control, the reaction pathways whereby a molecule rearranges after excitation is a common and heavily studied theme in chemistry and physics today. A recent development has been the production of energetic photons in the 10-100 eV range, through high harmonic generation, with sufficient fluxes that they can be used as a beam to excite/ionize workable fractions of a macroscopic sample gas. Such photons are energetic enough to both excite and ionize the molecule. A doubly charged molecular ion typically breaks into charged fragments, and comprehensive momentum imaging technologies (known variously as COLTRIMS, reaction microscope, TRCIS, etc. 1) are available for measuring the full momentum vectors of all charged reaction products, including both ions and electrons. Following the impulsive production of an excited ionic molecule by an ultrashort EUV pulse, the fragmentation pathway can be steered using a second strong infrared pulse whose intensity, waveform and timing are control parameters. We propose to study such processes by combining the momentum-imaging expertise of one institution (KSU) with the high harmonic-generation expertise of another (MPQ).