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Free keywords:
RESOLUTION INFRARED-SPECTROSCOPY; SUPERFLUID-HELIUM DROPLETS; SINGLE SF6 MOLECULES; ELEMENTARY EXCITATIONS; SPIN FLUCTUATIONS; ZERO-SOUND; LIQUID-HE-3; NANODROPLETS; CLUSTER
Abstract:
The absorption spectra of the S-1 <- S-0 electronic transition of a glyoxal molecule (C2H2O2) embedded inside a pure Fermionic He-3 droplet shows a sharp zero-phonon excitation line followed by a slowly decreasing wing extending to higher frequencies. Superimposed upon the wing, a small but sharp peak is observed at Delta E = 0.99 meV. The wing is shown to be due to the continuum of particle-hole pair excitations while the sharp peak results from the excitation of localized phonons of the snowball shell of He-3 atoms surrounding the chromophore molecule. The exceptional sharpness of the observed phonon peak (at least 10 times narrower than the ordinary bulk phonon peak at the same energy) is attributed to the localization associated with Friedel-like oscillations of the He-3 liquid density. Copyright (c) EPLA, 2009
