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Andrey Vilesov

Professor of Chemistry, Physics and Astronomy
Physical Chemistry

Habilitation,1999, University of Gottingen
Ph.D., 1985, St Petersburg State University
M.Sc., 1981, St Petersburg State University
Office: SSC 723
Phone: (213) 821-2936
Fax: (213) 740-3972
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Research Focus


The study of molecules and molecular aggregates in helium droplets is one of the most active and dynamically developing fields of modern physical chemistry. Helium is a superfluid below 2.17 K, displaying a number of unique and often counterintuitive properties such as vanishingly small viscosity and second sound. Our previous laser spectroscopic experiments have revealed that single molecules captured by He droplets possess extremely narrow spectral lines compared with other molecular beam experiments, indicating droplets are an ideal matrix for spectroscopic interrogation of large molecules and clusters. Embedded molecules rotate freely in the droplets providing a precise probe of their temperature (T = 0.38 K in 4He) and a probe of superfluidity on an atomic scale.

Our research focuses on chemistry and physics in ultra-cold helium and hydrogen clusters. This includes:

  • Observation of coherent rotation of molecules in superfluid He droplets
  • Use of molecules as a microscopic probe for superfluidity
  • Searching for superfluidity in hydrogen clusters
  • Synthesis and spectroscopy of molecular clusters inside He droplets
  • Study of low temperature aggregation in He droplets
  • Development of techniques for production and characterization of very large He droplets
  • Quantum vortices in He droplets
  • X-ray diffraction imaging of He droplets and embedded clusters

Recently we collaborated with researchers from SLAC at Stanford, LBNL and UC at Berkeley, and the Max-Planck-Institutes in Germany to study the existence and nature of quantum vortices in superfluid He droplets. In these experiments single, isolated, superfluid 4He droplets, containing ~ 108 - 1011 atoms, were studied using single-shot femtosecond X-ray coherent diffractive imaging. The formation of quantum vortex lattices inside the droplets, with densities up to 105 times higher than observed in bulk liquid He, was confirmed by observing characteristic Bragg patterns from Xe clusters trapped in the vortex cores. This high angular momentum leads to large centrifugal deformations of droplets and provides a direct probe of their angular velocity

Coherent diffraction imaging of single helium droplets with X-ray free electron laser. (Science 2014)

Bragg spots and lattice of vortices in He droplet. (Adapted from Science 2014).

Selected publications


  1. Gomez, L. F., Ferguson, K. R., Cryan, J. P., Bacellar, C., Tanyag, R. M. P., Jones, C., Schorb, S., Anielski, D., Belkacem, A., Bernando, C., Boll, R., Bozek, J., Carron, S., Chen, G., Delmas, T., Englert, L., Epp, S. W., Erk, B., Foucar, L., Hartmann, R., Hexemer, A., Huth, M., Kwok, J., Leone, S. R., Ma, J. H. S., Maia, F. R. N. C., Malmerberg, E., Marchesini, S., Neumark, D. M., Poon, B., Prell, J., Rolles, D., Rudek, B., Rudenko, A., Seifrid, M., Siefermann, K. R., Sturm, F. P., Swiggers, M., Ullrich, J., Weise, F., Zwart, P., Bostedt, C., Gessner, O., and Vilesov, A. F. Shapes and vorticities of superfluid helium nanodroplets. Science 345, 906-9 (2014).
  2. Gomez, L. F., Loginov, E., and Vilesov, A. F. Traces of Vortices in Superfluid Helium Droplets. Physical Review Letters 108, 155302-1-5 (2012).
  3. Loginov, E., Gomez, L. F., Chiang, N., Halder, A., Guggemos, N., Kresin, V. V., and Vilesov, A. F. Photoabsorption of AgN(N = 6-6000) Nanoclusters Formed in Helium Droplets: Transition from Compact to Multicenter Aggregation. Physical Review Letters 106, 233401-1-4 (2011).
  4. Gomez, L. F., Loginov, E., Sliter, R., and Vilesov, A. F. Sizes of large He droplets. Journal of Chemical Physics 135, 154201-1-9 (2011).
  5. Flynn, S. D., Skvortsov, D., Morrison, A. M., Liang, T., Choi, M. Y., Douberly, G. E., and Vilesov, A. F. Infrared Spectra of HCl-H2O Clusters in Helium Nanodroplets. Journal of Physical Chemistry Letters 1, 2233-2238 (2010).
  6. Skvortsov, D. S. and Vilesov, A. F. Using He droplets for measurements of interconversion enthalpy of conformers in 2-chloroethanol. Letter - Journal of Chemical Physics 130, 151101-1-4 (2009).
  7. Kuyanov-Prozument, K. and Vilesov, A. F. Hydrogen Clusters that Remain Fluid at Low Temperature. Physical Review Letters 101, 205301-1-4 (2008).
  8. Slipchenko, M. N., Kuyanov, K. E., Sartakov, B. G., and Vilesov, A. F. Infrared intensity in small ammonia and water clusters. Let J Chem Phys 124, 241101-1-4 (2006).
  9. Toennies, J. P. and Vilesov, A. F. Superfluid helium droplets: A uniquely cold nanomatrix for molecules and molecular complexes. Angewandte Chemie-International Edition 43, 2622-2648 (2004).
  10. Grebenev, S., Toennies, J. P., and Vilesov, A. F. Superfluidity within a small helium-4 cluster: The microscopic Andronikashvili experiment. Science 279, 2083-2086 (1998).
  11. Hartmann, M., Miller, R. E., Toennies, J. P., and Vilesov, A. Rotationally Resolved Spectroscopy of SF6 in Liquid-Helium Clusters - a Molecular Probe of Cluster Temperature. Physical Review Letters 75, 1566-1569 (1995).

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