Unraveling the Absorption Spectra of Alkali Metal Atoms Attached to Helium Nanodroplets

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• 作者：Oliver Bü ; nermann ; Georg Droppelmann ; Alberto Hernando ; Ricardo Mayol ; Frank Stienkemeier
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：December 13, 2007
• 年：2007
• 卷：111
• 期：49
• 页码：12684 - 12694
• 全文大小：412K
• 年卷期：v.111,no.49(December 13, 2007)
• ISSN：1520-5215

文摘

The absorption spectra of the first electronic exited state of alkali metal atoms on helium nanodroplets formedof both ⁴He and ³He isotopes were studied experimentally as well as theoretically. In the experimental partnew data on the 2p 2s transition of lithium on ³He nanodroplets are presented. The absorption spectrumchanges drastically when compared to ⁴He droplets, in contrast to sodium where only marginal differenceswere observed in former studies. To explain these large differences and to answer some still open questionsconcerning the interaction of alkali metal atoms with helium nanodroplets, a model calculation was performed.New helium density profiles as well as a refined model allowed us to achieve good agreement with theexperimental findings. For the first time the red-shifted intensities in the lithium and sodium spectra areexplained in terms of enhanced binding configurations in the excited state displaced spatially from the groundstate configurations.