AFM MOLECULAR IMAGES DURING TIP-INDUCED SURFACE MODIFICATION ON THE (010)-SURFACE OF A KCP(BR) SINGLE-CRYSTAL

Molecular-resolution images of an electrochemically prepared single cr ystal of potassium tetracyanoplatinate bromide complex (KCP(Br)) were recorded by atomic force microscopy during a tip-induced surface-modif ication process in which the probing tip scraped off the topmost surfa ce layer by layer. Two kinds of molecular images on the (010) face of the KCP(Br) crystal correspond to alternate layered structures consist ing of tetracyanoplatinate layers and interstitial ions. One molecular arrangement was assigned to cyanide Ligands and interstitial K+ and B r- ions, in good agreement with that obtained from X-ray diffraction. The other corresponds to rearranged interstitial ion (K+ and Br-) laye r. The rearrangement of the interstitial ions during the tip-induced s urface modification involves both loss of half of the K+ ions so as to preserve electroneutrality of the surface and to stabilize the disloc ations of the remaining ions. The present AFM imaging process during t he tip-induced surface modification provides mechanistic information o n molecular and ionic arrangements on the topmost surface.