We know, a particle may be represented by a wave PACKET which has a group velocity. But most of the time, we are concerned with the wave FUNCTION of a moving particle. In the de broglie hypothesis, it is said that a wave equation y=e^i(kx-wt), CANNOT be associated with a moving particle as the phase velocity comes out greater than that of light. But , in *deriving* / or arriving at the schroedinger's eqn, we assume a wave function of a free particle as the gen. wave travelling wave eqn.(of course, we assume it to be complex) I don't know, I am getting confused between the relationship between the wave packet of a particle and it's wave function.