J. Paraszczak, J.M. Shaw, et al.
Micro and Nano Engineering
The density of vibrational states in a fractal silica aerogel of Hausdorff dimension D≃2.4 has been determined using spin-echo neutron spectroscopy. A smooth phonon-fracton crossover is found with a fracton spectral dimension of {Mathematical expression}. This direct measurement of {Mathematical expression} near crossover agrees with a previous finding based on scaling Brillouin-spectroscopy results obtained with several samples. We also show that protons adsorbed in the gel vibrate with substantially higher amplitude than the silica matrix. © 1990 Springer-Verlag.
J. Paraszczak, J.M. Shaw, et al.
Micro and Nano Engineering
P. Martensson, R.M. Feenstra
Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
S.F. Fan, W.B. Yun, et al.
Proceedings of SPIE 1989
L.K. Wang, A. Acovic, et al.
MRS Spring Meeting 1993