Electronic Journal of Differential Equations, Vol. 2012 (2012), No. 85, pp. 1-36. Title: Existence and concentration of semiclassical states for nonlinear Schrodinger equations Author: Shaowei Chen (Capital Normal Univ., Beijing, China) Abstract: In this article, we study the semilinear Schrodinger equation $$ -\epsilon^2\Delta u+ u+ V(x)u=f(u),\quad u\in H^1(\mathbb{R}^N), $$ where $N\geq 2$ and $\epsilon>0$ is a small parameter. The function $V$ is bounded in $\mathbb{R}^N$, $\inf_{\mathbb{R}^N}(1+V(x))>0$ and it has a possibly degenerate isolated critical point. Under some conditions on f, we prove that as $\epsilon\to 0$, this equation has a solution which concentrates at the critical point of V. Submitted August 16, 2011. Published May 31, 2012. Math Subject Classifications: 35J20, 35J70. Key Words: Semilinear Schrodinger equation; variational reduction method.