Time-dependent density functional studies of multiple ionization of Ag-2 in an intense laser field (1.0 x 10(14) W/cm(2)) are presented. Special emphasis is placed on elucidating frequency dependence and effects of the d electrons on the ionization processes. We have found that the s and d electrons move reciprocally toward the opposite directions in a manner such that the electric field induced by the s-electron polarization is cancelled out by the d electrons. This screening effect of the d electrons suppresses the multiple ionization in marked contrast to molecular systems such as alkali metal clusters which do not accompany inner d-electrons. (c) 2005 Elsevier B.V. All rights reserved.