As the deuteron approaches the target nucleus, it is repelled by the electrostatic field, converting kinetic energy to potential energy until, assuming the energy is not sufficient for it to surmount the barrier, the deuteron approaches to a minimum distance.
As the deuteron approaches the target nucleus, it is deaccelerated by the electrostatic field, converting kinetic energy to potential energy, as with the compression of a spring. Depending on its energy, and assuming that the energy is not sufficient for it to surmount the barrier, it will approach to a minimum distance.