An effective approach for simulating the periodic motion of an overdamped p
article subjected to a multiplicative white-noise source is described. The
accurate calculations for the velocity of the particle and its correlation
function can be realized by introducing an inertial term. The results show
that fluctuation around a time-averaged quantity increases with decreasing
time step in the overdamped white-noise algorithm, however, a massive white
-noise technique greatly reduces this spurious drift. In particular, thr pr
esent algorithm converges on the correct values of the calculated quantitie
s while the mass of the particle approaches to zero.