Molecules and Clusters in Helium Nanodroplets: Chaotic, Collective, and Anionic States

氦纳米液滴中的分子和团簇：混沌态、集体态和阴离子态

• 批准号: 0245102
• 负责人: Curt Wittig
• 金额: --
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2007-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0245102&HistoricalAwards=false
• 关键词: Molecules; Clusters; Helium; Nanodroplets; Chaotic

Complementary experimental probes are applied to studies of the dynamics of small clusters and molecules residing in/on superfluid helium nanodroplets, Hen, where n is the number of He atoms. The aim is to use the Hen media to probe a number of fundamental dopant properties. The following topics are explored: (i) quantum chaotic dynamics in a superfluid environment (ii) the low-temperature limit of the lifetime of collective excitations in metal clusters; (iii) the formation and desorption of molecular and cluster anions in helium droplets by using low-energy electron capture. Photodepletion signals are enhanced greatly by using a novel "atomic feedback" strategy. Namely, a tube surrounding the counterpropagating droplet and laser beams constrains helium atoms that are evaporated as a result of photoabsorption by Hen clusters containing embedded impurities, and reuses these atoms to further deplete the droplet beam, in an avalanche-like effect. On a broader impact, the program enhances education via workshops, summer school programs, interdisciplinary programs and undergraduate involvement in the research.

互补实验探针被应用于研究居住在超流氦纳米液滴Hen中的小簇和分子的动力学，其中n是He原子的数目。目的是使用Hen介质来探测一些基本的掺杂物性质。探讨了以下主题：(i)超流体环境中的量子混沌动力学（ii）金属团簇中集体激励寿命的低温极限；（iii）利用低能电子捕获，在氦滴中形成和解吸分子阴离子和簇阴离子。用光信号通过使用一种新的“原子反馈”策略大大增强。也就是说，围绕反向传播的液滴和激光束的一根管子限制了氦原子，这些氦原子由于含有嵌入杂质的Hen团簇的光吸收而蒸发，并再利用这些原子进一步耗尽液滴光束，产生雪崩般的效果。在更广泛的影响上，该项目通过研讨会、暑期学校项目、跨学科项目和本科生参与研究来提高教育水平。