Electron attachment leads to unidirectional in-plane molecular rotation of para-chlorostyrene on Si(100)

TY - JOUR

T1 - Electron attachment leads to unidirectional in-plane molecular rotation of para-chlorostyrene on Si(100)

AU - Guo, Si Yue

AU - Timm, Matthew J.

AU - Huang, Kai

AU - Polanyi, John C.

N1 - Publisher Copyright: Copyright © 2019 American Chemical Society.

PY - 2019/8

Y1 - 2019/8

N2 - We report the observation of electron-induced unidirectional planar molecular rotation of para-chlorostyrene on Si(100), studied by scanning tunneling microscopy (STM) at room temperature and by ab initio theory. This bifunctional molecule is shown to be favorable to the electron-induced rotation since the phenyl group acts as a pivot and the vinyl as a lever arm. In the initial configuration, both phenyl and vinyl are attached to silicon dimers along the same row of the substrate. The first electron from the STM tip is observed to induce a lateral shift of the vinyl to "state 1" in which the vinyl is bound asymmetrically to one side of a silicon dimer. The second electron is found to give rise to a ∼60° rotation to "state 2", a configuration in which the vinyl has swung around the phenyl to an adjacent dimer row. The impulsive two-state (I2S) model was employed to explain the conversion of the initial state to state 1 and the conversion of state 1 to state 2. These two successive impulses were computed by the I2S model to be the result of excitation to different configurations in an anionic excited state. Following addition of the second electron, the repulsion between the asymmetric vinyl and the surface was shown to give rise to a torque with the magnitude and direction required to explain the observed rotation.

AB - We report the observation of electron-induced unidirectional planar molecular rotation of para-chlorostyrene on Si(100), studied by scanning tunneling microscopy (STM) at room temperature and by ab initio theory. This bifunctional molecule is shown to be favorable to the electron-induced rotation since the phenyl group acts as a pivot and the vinyl as a lever arm. In the initial configuration, both phenyl and vinyl are attached to silicon dimers along the same row of the substrate. The first electron from the STM tip is observed to induce a lateral shift of the vinyl to "state 1" in which the vinyl is bound asymmetrically to one side of a silicon dimer. The second electron is found to give rise to a ∼60° rotation to "state 2", a configuration in which the vinyl has swung around the phenyl to an adjacent dimer row. The impulsive two-state (I2S) model was employed to explain the conversion of the initial state to state 1 and the conversion of state 1 to state 2. These two successive impulses were computed by the I2S model to be the result of excitation to different configurations in an anionic excited state. Following addition of the second electron, the repulsion between the asymmetric vinyl and the surface was shown to give rise to a torque with the magnitude and direction required to explain the observed rotation.

UR - http://www.scopus.com/inward/record.url?scp=85070544522&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcc.9b04076

DO - 10.1021/acs.jpcc.9b04076

M3 - 文章

AN - SCOPUS:85070544522

SN - 1932-7447

VL - 123

SP - 18425

EP - 18431

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

IS - 30

ER -