Experimental and theoretical study of the radial density distributions of large<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">He</mml:mi></mml:math>droplets

Harms, Jan; Toennies, J. P.; Barranco, M.; Pí, M.

doi:10.1103/physrevb.63.184513

Cited by 42 publications

(126 citation statements)

References 45 publications

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“…Cluster sizes for 3 He were determined using a cross-jet and pick-up method. 11 A rapid onset of clustering between 10.2 and 10.6 K, consistent with ref 11, can be seen with an average droplet size of 10 3 . Reference 11 reports decreasing droplet sizes with decreasing temperature.…”

Section: The Journal Ofsupporting

confidence: 80%

“…Measurements of the droplet size by Harms et al using the cross beam deflection method reveal sizes that decrease slightly with decreasing source temperature. 11 If we take the large distortion and intensity loss as indicators of the presence of very large droplets, our spectra show rather the opposite. We have therefore indicated the size only for source temperatures close to the onset of clustering where we believe the assignment by Harms et al is reliable.…”

Section: The Journal Ofmentioning

confidence: 83%

“…Compared to the early days of such research on helium clusters, reliable data of the average cluster sizes produced at specific source conditions is now readily available. 11,13 The availability of this data allows a much better assignment of sizes than was possible in the early studies. Our method is to investigate both stable isotopes of helium, 3 He and 4 He.…”

Section: ' Introductionmentioning

confidence: 99%

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Size and Isotope Effects of Helium Clusters and Droplets: Identification of Surface and Bulk-Volume Excitations

et al. 2011

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The helium atom is the simplest example of a many-electron atom. In light of the simplicity and model character of helium atoms one would naturally be interested to learn how the electronically excited states become modified when an excited helium atom is placed near one, two, or more helium atoms. A straightforward experiment to investigate this problem is to produce a beam of helium clusters of variable size and to photoexcite these clusters in the vacuum ultraviolet (VUV) spectral range using synchrotron radiation. Such an experiment probes a disordered arrangement of atoms because helium clusters and droplets in a free beam are always liquid. A molecular beam of clusters is optically thin and absorbs very little light, but helium clusters have a large fluorescence yield. Therefore, photofluorescence yield detection is the method of choice. The first experiments of 4 He clusters of variable size using a VUV fluorescence light detector identified a number of bands and it was found that the energies of these excitations, unlike the electronic excitations of heavy rare gas clusters, 1,2 did not fit to a Wannier-type excitonic series. 3 Subsequent experiments investigated fluorescence decay channels in different wavelength regions, 4,5 the effect of helium particle density, 6 fluorescence in cavities within large helium droplets, 7 and the possible Rydberg nature of the excited states of small helium clusters. 8 First quantum chemical calculations of an octahedral model cluster reported the energies of the n = 2, 3, and 4 states of the central atom as a function of the internuclear separation in the octahedron. 9 Electronic spectra simulations of a perturbed octahedron as well as an N = 25 atom-large cluster 10 were able to reproduce previously reported experimental data of small clusters. 6 Despite these efforts, we still have an incomplete picture of the electronically excited states of large helium clusters. The number of states increases dramatically with size making the computation and interpretation of the results laborious. The availability of experimental data that cover the entire size range of helium clusters and droplets is prerequisite as a benchmark for testing theoretical interpretation and likewise prerequisite in providing evidence for empirical interpretation. Furthermore, the comprehensive data set presented in this paper shows that each helium cluster size has a specific spectral fingerprint. A unique feature of helium clusters and droplets is the 6À7 Å thick surface region where the density drops smoothly from the bulk value to zero. 11,11,12 With regard to electronically excited states, such a surface layer represents a ABSTRACT: We report a comprehensive investigation of the electronically excited states of helium clusters and droplets of sizes ranging from a few to several 10 7 atoms using time-resolved fluorescence excitation spectroscopy and quantum chemical ab initio calculations. We employ various approaches for our analysis considering the lifetime-dependence of the fluorescence intens...

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Section: The Journal Ofsupporting

confidence: 80%

Section: The Journal Ofmentioning

confidence: 83%

Section: ' Introductionmentioning

confidence: 99%

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Size and Isotope Effects of Helium Clusters and Droplets: Identification of Surface and Bulk-Volume Excitations

et al. 2011

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“…Absolute sizes have been measured by means of deflection in scattering experiments [29,24,30] or attachment of electrons and deflection in electric fields [31]. The reason why most of the spectroscopic experiments have been performed in the size range around 5000 helium atoms can be seen in Fig.…”

Section: Production Of Helium Nanodroplets and Source Designmentioning

confidence: 99%

Spectroscopy and dynamics in helium nanodroplets

Stienkemeier

Lehmann

2006

J. Phys. B: At. Mol. Opt. Phys.

398

555

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Abstract. This article provides a review of recent work in the field of helium nanodroplet spectroscopy with emphasis on the dynamical aspects of the interactions between molecules in helium as well as their interaction with this unique quantum solvent. Emphasis is placed on experimental methods and studies introducing recent new approaches, in particular including time-resolved techniques. Corresponding theoretical results on the energetics and dynamics of helium droplets are also discussed.

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“…However, current experiments sometimes have to deal with situations that cannot be addressed by fully microscopic methods. We can mention, for example, the description of very large 4 He and 3 He drops 35,36 , or the structure of large mixed drops already discussed. As a matter of fact, in spite of the recent progress made in the variational description 26 of small (up to 40 atoms) 3 He droplets, a simultaneous description of ground state and elementary excitations of pure 3 He droplets has been only obtained within the density functional theory, using either zero-range 37,38 or finite-range density functionals [39][40][41][42] .…”

Section: Introductionmentioning

confidence: 99%

Multipole response of doped He3 drops

Garcías¹,

Serra²,

Casas³

et al. 2001

The Journal of Chemical Physics

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The multipole response of 3 HeN drops doped with very attractive impurities, such as a Xe atom or an SF6 molecule, has been investigated in the framework of the Finite Range Density Functional Theory and the Random Phase Approximation. We show that volume (L = 0) and surface (L = 1, 2) modes become more fragmented, as compared with the results obtained for pure 3 HeN drops. In addition, the dipole mean energy goes smoothly to zero when N increases, indicating that for large N values these impurities are delocalized in the bulk of the drop.

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Experimental and theoretical study of the radial density distributions of large3Hedroplets

Cited by 42 publications

References 45 publications

Size and Isotope Effects of Helium Clusters and Droplets: Identification of Surface and Bulk-Volume Excitations

Size and Isotope Effects of Helium Clusters and Droplets: Identification of Surface and Bulk-Volume Excitations

Spectroscopy and dynamics in helium nanodroplets

Multipole response of doped He3 drops

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