Intrinsic Gap Mode Eigenvector in FCC Structure
You can move the crystal draging it with the mouse.
The intrinsic localized gap mode vibrating in the
 direction is shown for fcc lattice of NaI crystal.
The amplitude of the central Na-ion is 24% of the nearest-neighbor
The frequency of the shown intrinsic gap mode
lies 5% down in the gap between optic and acoustic phonon bands
The magnitude of the axial elastic distortion is enhanced
by 5 times for clearity.
Small circles, Na+ ions; large circles, I-
Last modified: April 3, 1997