%0 Journal Article %T Spectral shift function for slowly varying perturbation of periodic Schr£¿dinger operators %A Dimassi %A Mouez %A Zerzeri %A Maher %J Cubo (Temuco) %D 2012 %I Scientific Electronic Library Online %R 10.4067/S0719-06462012000100004 %X in this paper we study the asymptotic expansion of the spectral shift function for the slowly varying perturbations of periodic schr£¿dinger operators. we give a weak and pointwise asymptotic expansions in powers of h of the derivative of the spectral shift function corresponding to the pair(p(h) = p0 + ¦Õ (hx); p0 = -¦Ä+ v(x)) ; where is a decreasing function, o (|x|-¦Ä) for some ¦Ä> n and h is a small positive parameter. here the potential v is real, smooth and periodic with respect to a lattice t in rn. to prove the pointwise asymptotic expansion of the spectral shift function, we establish a limiting absorption theorem for p(h). %K periodic schr£¿dinger operator %K spectral shift function %K asymptotic expansions %K limiting absorption theorem. %U http://www.scielo.cl/scielo.php?script=sci_abstract&pid=S0719-06462012000100004&lng=en&nrm=iso&tlng=en