Eur. Phys. J. E (2003) 12: 9-12
https://doi.org/10.1140/epjed/e2003-01-003-7

Confined phonons in glasses

¹ Institut für Physikalische Chemie, Universität Stuttgart, 70569 Stuttgart, Germany
² Experimentalphysik E13, TU München, 85747 Garching, Germany
³ European Synchrotron Radiation Facility, B.P. 220, 38043 Grenoble, France
⁴ HAmburger SYnchrotronstrahlungsLABor at DESY, 22603 Hamburg, Germany
⁵ Russian Research Centre ‘Kurchatov Institute’, Moscow, 123182, Russia

^* e-mail: t.asthalter@ipc.uni-stuttgart.de

Received: 1 January 2003
Published online: 5 November 2003

Abstract

We have applied nuclear inelastic absorption (NIA) to the molecular glass former dibutyl phthalate/ferrocene, both in bulk and in nanoporous matrices having pore sizes of 50 and 25 Å. The quantity g(E)/E ², where g(E) is the vibrational density of states (VDOS) of the iron atoms, exhibits a pronounced maximum around 2 meV. Confinement in pores leads to a suppression of the VDOS below 1.5 meV, independent of the pore size. The influence of local interactions at the pore wall was assessed using Raman scattering. Our observations are discussed in the light of experimental and theoretical results on nanoparticles and for the Boson peak.