z≈a✉(1+ m2m2 (KT)2R6 (117) we obtain,in the desired order, (=kT nZ 0月 m2m 3kT () m2m2 1R =-2 kT RR' (118) which implies that the magnitude of the expectation value of the force is proportional to R-7.(117) we obtain, in the desired order, (118) which implies that the magnitude of the expectation value of the force is proportional to