  We study the zero temperature limit for interacting Brownian particles in one
dimension with a pairwise potential which is of finite range and attains a
unique minimum when the distance of two particles becomes a>0.
  We say a chain is formed when the particles are arranged in an ``almost
equal'' distance a. If a chain is formed at time 0, so is for positive time as
the temperature of the system decreases to 0 and, under a suitable macroscopic
space-time scaling, the center of mass of the chain performs the Brownian
motion with the speed inversely proportional to the total mass. If there are
two chains, they independently move until the time when they meet. Then, they
immediately coalesce and continue the evolution as a single chain. This can be
extended for finitely many chains.

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