Energy of an electrorheological solid calculated with inclusion of higher multipoles.

We have investigated the contributions of higher multipoles to the energy of an electrorheological solid. We find that, with the dipole and octupole moments taken into account, the fcc structure becomes almost degenerate in energy with the bct: Favoring of the latter is only by 1/10 to 1/4 of its dipole value. The thirty-two-pole effect is opposite to that of the octupole so that, when it is also added, the energy by which the bct structure is favored is restored to about 1/2 to 4/5 of its dipole value.