Neutron Scattering Studies of Quantum Systems

量子系统的中子散射研究

• 批准号: 9624762
• 负责人: Paul Sokol
• 金额: $ 18万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-01 至 1999-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9624762&HistoricalAwards=false
• 关键词: Neutron; Scattering; Studies; Quantum; Systems

9624762 Sokol Neutron scattering studies of quantum systems will be carried out in this research project. The behavior of the condensed phases of quantum liquids and solids, such as helium and hydrogen, are dominated by quantum and statistical effects which are responsible for many unique properties such as superfluidity. More recently, confinement of these systems in restricted geometries has shown that the properties can be substantially different from the bulk. Elastic and inelastic neutron scattering will be used to probe the microscopic structure and dynamics of these phases. This work will focus on the helium isotopes (3He and 4He), isotopic mixtures (3He-4He), and hydrogen (H2) where the properties of the condensed phase are dominated by quantum effects. Elastic and total neutron scattering measurements will provide information on the spatial correlation's. Inelastic neutron scattering measurements will be used to study diffusive motion, collective excitations, and the one-body density matrix. (momentum distribution). Measurements will be carried out in both bulk systems and for liquids and solids in confined geometries such as porous Vycor glass, aerogels and solgels, and zeolites. %%% Neutron scattering studies of quantum systems will be carried out in this research project. Quantum solids and liquids, such as helium and hydrogen to be studied, provide a useful model system for studying many of the quantum effects that are found in metals, superconductors, and magnetic materials. However, they do not suffer the same materials preparation problems so that the central physical principles are more easily extracted. Elastic and inelastic neutron scattering will be used to probe the microscopic structure and dynamics of these solid and liquid phases. These measurements will provide information on the static and dy namic interaction of helium atoms and hydrogen molecules in the condensed phases. This work will focus on the helium isotopes (3He and 4He), isotopic mixtures (3He- 4He), and hydrogen (H2) in both the bulk phases and in confined geometries. ***

9624762量子系统的Sokol中子散射研究将在该研究项目中进行。 量子液体和固体（例如氦气和氢）的冷凝阶段的行为以量子和统计效应为主，这些效应造成了许多独特的特性，例如超流体。 最近，这些系统在受限的几何形状中的限制表明，这些性能可能与大量大不相同。 弹性和非弹性中子散射将用于探测这些相的显微镜结构和动力学。 这项工作将集中在氦同位素（3HE和4HE），同位素混合物（3HE-4HE）和氢（H2）上，其中冷凝相的性质以量子效应为主。 弹性和总中子散射测量结果将提供有关空间相关性的信息。 非弹性中子散射测量将用于研究扩散运动，集体激发和单体密度基质。 （动量分布）。 测量将在散装系统和液体和固体中进行，例如多孔Vycor玻璃，气凝胶和溶胶和沸石。 该研究项目将进行量子系统的中子散射研究。 量子固体和液体（例如要研究的氦气和氢）提供了一个有用的模型系统，用于研究金属，超导体和磁性材料中发现的许多量子效应。 但是，它们不会遭受相同的材料准备问题，因此更容易提取中央物理原理。弹性和非弹性中子散射将用于探测这些固体和液相的微观结构和动力学。 这些测量值将提供有关凝结相中氦原子和氢分子的静态和DY NAMIC相互作用的信息。 这项工作将集中在氦同位素（3HE和4HE），同位素混合物（3HE-4HE）和氢（H2）和氢（H2）和氢（H2）和氢（H2）中。 ***