Mechanical Conformation Switching of a Single Pentacene Molecule on Si(100)-(2 × 1)

Abstract

The mechanical switching of a single pentacene molecule chemisorbed in a planar configuration along a dimer row of the Si(100)-(2 × 1) surface was performed experimentally using the tip apex of a scanning tunneling microscope. The mechanical switching reaction path was identified theoretically on the ground state potential energy surface of the pentacene/Si(100)-(2 × 1) system. A low-temperature scanning tunneling microscope as well as semiempirical ASED+ molecular mechanical and elastic scattering quantum chemistry (ESQC) calculations were employed to perform the studies. Pushing with the STM tip apex and at zero bias voltage exactly at the center of the chemisorbed pentacene molecule induces a mechanical conformation change of the pentacene from its metastable to its surface stable conformation on the Si(100)-(2 × 1) surface.