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

University Of Southern California, Los Angeles CA

Investigators

Abstract

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.