Constructing slow modes of
from free modes of
 
 
Xi
1. Make an independent set of free modes of      (dR1dR5).
These create gaps (only) at the 5 contacts
2. Construct trial modes (dR*1dR*5) from (dR1dR5) to close these gaps
E g, displacement of particle i for mode 1
L
dR*1,i = dR1,i  sin(2pXi/L)
3. Select (dR1dR5) so that (dR*1dR*5)  are orthogonal.
4. Trial modes have low energy, hence low average frequency w(L)~1/L
Éabout as low as lowest acoustic modes of these particles
Thus there are 5 normal modes of         with average frequency   < w(L)