%0 Journal Article %T Semi-classical analysis of the Laplace operator with Robin boundary conditions %A Rupert L. Frank %A Leander Geisinger %J Bulletin of Mathematical Sciences %@ 1664-3615 %D 2012 %I Springer %R 10.1007/s13373-012-0028-5 %X We prove a two-term asymptotic expansion of eigenvalue sums of the Laplacian on a bounded domain with Neumann, or more generally, Robin boundary conditions. We formulate and prove the asymptotics in terms of semi-classical analysis. In this reformulation it is natural to allow the function describing the boundary conditions to depend on the semi-classical parameter and we identify and analyze three different regimes for this dependence. %U http://link.springer.com/article/10.1007/s13373-012-0028-5