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Free keywords:
LIQUID-HELIUM CLUSTERS; SINGLE SF6 MOLECULES; ROTATIONAL STRUCTURE; QUANTUM SOLVATION; EVAPORATION RATE; OCS; SPECTRA; ATOMS; NANODROPLETS; TEMPERATURE
Abstract:
The infrared spectrum of the ν 3 band of an OCS (carbonyl sulfide) molecule embedded inside pure 3He droplets of about 12 x 103 atoms reported in 1998 [S. Grebenev, J. P. Toennies, and A. F. Vilesov, Science 279, 2083 (1998)] is carefully evaluated. The spectrum, which consists of a broad central peak and a distinct shoulder at lower energy, was analyzed by assuming unresolved rotational line structure of either a linear or a symmetric top. In each case the spectrum was fitted using either Lorentzian or Gaussian peak shapes with a preassigned fixed temperature of 0.15 K or a best fit temperature. Many of the fits describe the spectra nearly equally well and indicate broad R0, R1, and P1 peaks but no Q-branch, a moment of inertia which is about a factor six greater than for the free molecule, and a temperature of 0.07 +/- 0.06 K which is significantly less than 0.15 K determined for mixed 3He/4He droplets. The increased moment of inertia is consistent with about 11 attached 3He atoms which take part in the end-over-end rotations of the chromophore. The large line widths are attributed to creation of particle-hole pair excitations in the fermionic droplets. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3697475]
