  This article deals with the spectral analysis of the semiclassical Neumann
magnetic Laplacian on a smooth bounded domain in dimension three. When the
magnetic field is constant and in the semiclassical limit, we establish a
four-term asymptotic expansion of the low-lying eigenvalues, involving a
geometric quantity along the apparent contour of the domain in the direction of
the field. In particular, we prove that they are simple.
