Effect of the Van Hove singularities on the X-ray absorption and emission in metals
Gogolin A.O.
The process of relaxation to a suddenly created local potential is studied for a (quasi-) two-dimensmal metals with Van Hove points near the Fermi surface. The new intermediate time-asymptotic for the core hole Green's function is found. It turns out, that the problem can not be described in terms of creation of independent electron-hole pairs.