  In this paper, we prove the decay and scattering in the energy space for
nonlinear Schr\"odinger equations with regular potentials in $\Bbb R^d$ namely,
$i{\partial _t}u + \Delta u - V(x)u + \lambda |u|^{p - 1}u = 0$. We will prove
decay estimate and scattering of the solution in the small data case when
$1+\frac{2}{d}<p\le1+\frac{4}{d-2}$, $d\ge3$. The index $1+\frac{2}{d}$ is
sharp for scattering concerning the result of W. Strauss [21].
