The DX centre
T.N. Morgan
Semiconductor Science and Technology
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.
T.N. Morgan
Semiconductor Science and Technology
Joy Y. Cheng, Daniel P. Sanders, et al.
SPIE Advanced Lithography 2008
M.A. Lutz, R.M. Feenstra, et al.
Surface Science
R.W. Gammon, E. Courtens, et al.
Physical Review B