ULTRAFAST TIME RESOLVED LAUE DIFFRACTION ON DI-RHODIUM COMPLEXES

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。所列机构为 中心，不一定是研究者的机构。 本实验旨在为研究分子单晶中的光激发过程提供实验数据。最初的光激发过程发生在极短的时间尺度上（飞秒/皮秒时域），并且由于其可能的应用（例如作为光开关）而一直是科学研究的焦点。在光激发之后，可以在单晶中形成几种物质，其中一些物质的寿命长达几毫秒。我们建议进行时间分辨劳厄衍射以下的光激发不同的激光强度的金属配体分子晶体。这些化合物在光生电子自旋翻转三重态方面具有非凡的特性。这种机制的一个直接应用是建立在光学发光二极管的功能设计中。在不同温度下进行的拟议实验将为光致结构机制提供额外的内部。这应该提供有关的结构动力学的基础上的人口和光激发的物种在晶体中的衰变机制的信息，澄清热传递和人口的结构状态，可以积极地用于发光应用的基本问题。作为样品，我们选择了Rh 2（1，8-diisocyano-p-menthane）4（PF 6）2 CH 3CN（Rh-dimen），这是一种已知在15 K至室温的温度下在100 ns-μ s时间尺度内产生激发态的化合物。1.9%（532 nm激发）和2.5%（355 nm）的激发态人口已经在微秒时间分辨率的实验中得到了改善。从超快光学实验（在内部研究），我们预计人口的光活性三重态的高达5%的400 nm的激发与100 fs的激光pulses.We建议，首先调查在响应的晶体更高的激光强度，然后进行温度相关的测量。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The experiment aims at providing experimental data for an investigation of photo-excitation processes in molecular single-crystals. The initial photo-excitation processes occur on extremely short time-scales (femto-/picosecond time domain) and have been in the focus of scientific investigations due to their possible applications, e.g. as optical switches. Following optical excitation several species can be formed in a single crystal, some of which live up to some milliseconds. We propose to carry out time-resolved Laue diffraction following photo-excitation for varying laser intensities on metal-ligand molecular crystals. These compounds have extraordinary characteristics in photo-producing electron-spin flipped triplet states. One direct application of this mechanism is built in the functional design of optical light emitting diodes. The proposed experiments carried out at different temperatures will give an additional inside into the photo-induced structural mechanism. This should provide information about the structural dynamics underlying the population and decay mechanism of the photoexcited species in crystals clarifying fundamental questions of heat transfer and population of structural states which can actively be used for light-emitting application. As sample we have selected Rh2(1,8-diisocyano-p-menthane)4(PF6)2·CH3CN (Rh-dimen), a compound that is known to produce exited states in the single crystal with varying lifetimes in the 100 ns-¿s timescales at temperatures from 15 K to room temperature. Excited state populations of 1.9% (532 nm excitation) and 2.5% (355 nm) have already been refined in experiments with microsecond time resolution. From ultrafast optical experiments (in house research) we expect populations of the light-active triplet state of up to 5% for 400 nm excitation with 100 fs laser pulses.We propose to first investigate in the response of the crystal to higher laser intensities and then carry out temperature dependent measurements.