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Uilta high resolution spectroscopy of excitons in quantum crystal

量子晶体中激子的 Uilta 高分辨率光谱

基本信息

批准号：
09304040
负责人：
MOMOSE Takamasa
金额：
$ 22.08万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

A crystal of parahydrogen, in which nearly all the molecules are in the J=0 rotational state, is known as a quantum crystal. An exceptional feature of the crystal is its narrow spectral linewidth. Here, we have studied parahydrogen molecule itself and molecules embedded in parahydrogen crystal by high-resolution spectropscopy. From the analysis of fine structures, frequency shifts and spectral lineshape of the rotation-vinbration transitions, we have investigated specific nature of excitons and its relaxation dynamics in the quantum crystal. Some of the results are summarized as follows. (1) The first overtone vibrational transition of parahydrogen has been studied by high-resoultion laser spectroscopy. The fine spliting was interpreted as due to vibron hopping in the quantum crystal. Also, the quantum effect on the vibron could be discussed.(2) Temperature dependence on the linewdith of methane embedded in parahydrogen reveals that pure dephasing is predominant as the cause of the relaxation at low temperatures, but the dependence was completely different from those in classical solids. Moreover the polulation relaxation was found to strongly depend on the shape of vibrational modes.(3) Infrared absorption of gamma-ray irradiated parahydrogen has been studied. Infrared absorption of hydrogen molecules induced by ions produced by the irradiation was analyzed quantitatively. We have developed a new method to detect ions selectively by applying external electric field to the crystal.

仲氢的晶体，其中几乎所有的分子都处于J=0旋转状态，被称为量子晶体。该晶体的一个特殊特征是其窄光谱线宽。本文利用高分辨光谱技术研究了仲氢分子本身和嵌在仲氢晶体中的分子。从转动振动跃迁的精细结构、频移和谱线形状的分析出发，研究了量子晶体中激子的特殊性质及其弛豫动力学。部分结果总结如下。(1)用高分辨激光光谱研究了仲氢分子的第一泛频振动跃迁。精细分裂被解释为由于量子晶体中的振动子跳跃。此外，还讨论了振动子的量子效应。(2)嵌入仲氢的甲烷的线宽的温度依赖性表明，纯退相是主要的原因在低温下的松弛，但依赖性是完全不同的经典固体。此外，发现极化弛豫强烈依赖于振动模式的形状。(3)本文研究了γ射线辐照仲氢的红外吸收。定量分析了辐照产生的离子对氢分子红外吸收的影响。我们发展了一种通过外加电场对晶体进行选择性离子检测的新方法。