Direct visualization in manipulation of stable molecular radicals at room temperature

We present a novel approach for room-temperature molecular manipulation which exploits the reduced thermal mobility of chemisorbed molecular radicals, with cyclopentadienyl, C5H5, on Ag(100) as an example. Several novel manipulation modes are demonstrated, all achieved at room temperature. Most notably, the dynamics of the radicals can be directly visualized during manipulation, revealing their preferred direction of motion to be perpendicular to the tip displacement. Additionally, individual radicals can be selectively desorbed intact. These findings point to the feasibility of controlling surface chemistry and molecular engineering down to the fundamental ligand level. (C) 1997 Elsevier Science B.V.