Asymptotic of the dissipative eigenvalues of Maxwell's equations

Let Omega = R-3 \ (K) over bar, where K is an open bounded domain with smooth boundary Gamma. Let V (t) = e(tGb), t >= 0, be the semigroup related to Maxwell's equations in Omega with dissipative boundary condition nu boolean AND ( nu boolean AND E) + gamma (x)(nu boolean AND H) = 0, gamma (x) > 0, for all x is an element of Gamma. We study the case when gamma (x) not equal 1, for all(x) is an element of Gamma, and we establish a Weyl formula for the counting function of the eigenvalues of Gb in a polynomial neighbourhood of the negative real axis.