Injection of Atoms and Molecules in a Superfluid Helium Fountain: Cu and Cu2Hen (n = 1, ..., 鈭?

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• 作者：Esa Vehmanen ; Vahan Ghazarian ; Courtney Sams ; Isahak Khachatryan ; Jussi Eloranta ; V. A. Apkarian
• 刊名：Journal of Physical Chemistry A
• 出版年：2011
• 出版时间：June 30, 2011
• 年：2011
• 卷：115
• 期：25
• 页码：7077-7088
• 全文大小：1283K
• 年卷期：v.115,no.25(June 30, 2011)
• ISSN：1520-5215

文摘

We introduce an experimental platform designed around a thermomechanical helium fountain, which is aimed at investigating spectroscopy and dynamics of atoms and molecules in the superfluid and at its vapor interface. Laser ablation of copper, efficient cooling and transport of Cu and Cu₂ through helium vapor (1.5 K < T < 20 K), formation of linear and T-shaped Cu₂鈭扝e complexes, and their continuous evolution into large Cu₂鈭扝e_n clusters and droplets are among the processes that are illustrated. Reflection is the dominant quantum scattering channel of translationally cold copper atoms (T = 1.7 K) at the fountain interface. Cu₂ dimers mainly travel through the fountain unimpeded. However, the conditions of fountain flow and transport of molecules can be controlled to demonstrate injection and, in particular, injection into a nondivergent columnar fountain with a plug velocity of about 1 m/s. The experimental observables are interpreted with the aid of bosonic density functional theory calculations and ab initio interaction potentials.