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A scientific session of the Physical Sciences Division of the Russian Academy of Sciences dedicated to the 40th anniversary of the Institute of Spectroscopy, RAS (ISAN) was held at ISAN on 8 October 2008. The following reports were presented at the session: (1) Balykin V I (ISAN) "Atom optics and nanotechnology"'; (2) Ryabtsev A N, Churilov S S (ISAN) "Spectroscopy of ionized atoms for astrophysics and nanotechnology"; (3) Lozovik Yu E (ISAN) "Strong correlations and new phases in a system of excitons and polaritons. A polariton laser"; (4) Vinogradov E A, Mavrin B N, Novikova N N, Yakovlev V A (ISAN) "Inverted optical phonons in ion-covalent crystals"; (5) Mal'shukov A G "Spin transport in semiconductor microstructures"; (6) Dumesh B S, Potapov A V, Surin L A (ISAN) "Spectroscopy of small helium clusters and 'nanoscopic' superfluidity: HeN – CO, N = 2 – 20..."; (7) Naumov A V, Vainer Yu G (ISAN) "Single molecules as spectral nanoprobes for the diagnostics of dynamic processes in solid media"; (8) Kompanets O N (ISAN), Yevdokimov Yu M (Engelhardt Institute of Molecular Biology, RAS) "Optical biosensors of genotoxicants based on DNA nanoconstructions and portable dichrometer." A brief presentation of these reports, with the exception of report 5, is given below. • Atom optics and nanotechnology, Physics-Uspekhi, 2009, Volume 52, Number 3, Pages 275–282 • Spectroscopy of ionized atoms for astrophysics and nanotechnology, Physics-Uspekhi, 2009, Volume 52, Number 3, Pages 282–286 • Strong correlations and new phases in a system of excitons and polaritons. A polariton laser, Physics-Uspekhi, 2009, Volume 52, Number 3, Pages 286–290 • Inverted optical phonons in ion-covalent crystals, Physics-Uspekhi, 2009, Volume 52, Number 3, Pages 290–293 • Spectroscopy of small helium clusters and 'nanoscopic' superfluidity: HeN – CO, N = 2 – 20..., Physics-Uspekhi, 2009, Volume 52, Number 3, Pages 294–298 • Single molecules as spectral nanoprobes for the diagnostics of dynamic processes in solid media, Physics-Uspekhi, 2009, Volume 52, Number 3, Pages 298–304 • Optical biosensors of genotoxicants based on DNA nanoconstructions and portable dichrometer., Physics-Uspekhi, 2009, Volume 52, Number 3, Pages 304–309

This paper reviews research on helium clusters (of up to 20 atoms) and molecular hydrogen clusters (of up to 17 molecules) weakly bound by van der Waals forces to a light chromophore molecule such as OCS, N2O, CO2, or CO. Such clusters form in supersonic gas jets and are studied through the spectrum of the particular chromophore used. It is found that as the cluster grows, its rotational frequency increases (the effective moment of inertia decreases) starting from a certain number of atoms (molecules) attached. Also, in CO-based clusters a nearly free rotation of the chromophore molecule was observed. Experimental studies of such clusters are reviewed, as are those of the N2–CO and CO–CO complexes in which both monomers nearly freely rotate. The relation of these rotations to the superfluidity of helium and hydrogen is discussed, and comparisons are made with spectroscopic experiments on chromophores and hydrogen clusters in liquid helium nanodroplets.