In our calculations of weak interactions in transition metal complexes some rather unusual contributions due to excitations from relatively inert subvalence electronic shells have been observed for copper interacting with water and ammonia. These contributions are analyzed in terms of cluster amplitudes which indicate that the copper-molecule interaction considerably increases the near degeneracy of atomic states. The t(1) amplitude associated with the 3d --> 4s excitation rapidly increases with the decrease of the copper-molecule distance. This, in consequence, leads to the increasing role of the 3p shell polarization. This effect is essentially absent in the case of silver complexes.