On the Schroedinger equation in $\mathbb{R}^{N}$ under the effect of a general nonlinear term

In this paper we prove the existence of a positive solution to the\ud equation $-\Delta u + V(x)u=g(u)$ in $\RN,$ assuming the general\ud hypotheses on the nonlinearity introduced by Berestycki \&\ud Lions. Moreover we show that a minimizing problem, related to the existence of a ground state, has no solution