TY  - JOUR
A1  - Gaebel, Tina
A1  - Bein, Daniel
A1  - Mathauer, Daniel
A1  - Utecht, Manuel
A1  - Palmer, Richard E.
A1  - Klamroth, Tillmann
T1  - Nonlocal STM manipulation of chlorobenzene on Si(111)-7 x 7
BT  - Potentials, kinetics, and first-principles molecular dynamics calculations for open systems
JF  - The journal of physical chemistry : C, Nanomaterials and interfaces
N2  - We use quantum chemical cluster models together with constrained density STM Ph CI functional theory (DFT) and ab initio molecular dynamics (AIMD) for open system to simulate tip and rationalize nonlocal scanning tunneling microscope (STM) manipulation experiments for Philh ci chlorobenzene (PhCl) on a Si(111)-7 X 7 surface. We consider three different processes, namely, the electron-induced dissociation of the carbon-chlorine bond for physisorbed PhCl molecules at low temperatures and the electron- or hole-induced desorption of chemisorbed PhCl at 300 K. All processes can be induced nonlocally, i.e., up to several nanometers (nm) away from the injection site, in STM experiments. We rationalize and explain the experimental findings regarding the STM-induced dissociation using constrained DFT. The coupling of STM-induced ion resonances to nuclear degrees of freedom is simulated with AIMD using the Gadzuk averaging approach for open systems. From this data, we predict a 4 fs lifetime for the cationic resonance. For the anion model, desorption could not be observed. In addition, the same cluster models are used for transition-state theory calculations, which are compared to and validated against time-lapse STM experiments.
Y1  - 2021
U6  - https://doi.org/10.1021/acs.jpcc.1c02612
SN  - 1932-7447
SN  - 1932-7455
VL  - 125
IS  - 22
SP  - 12175
EP  - 12184
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Utecht, Manuel Martin
A1  - Palmer, Richard E.
A1  - Klamroth, Tillmann
T1  - Quantum chemical approach to atomic manipulation of chlorobenzene on the Si(111)-7 x 7 surface
BT  - Resonance localization, vibrational activation, and surface dynamics
JF  - Physical review materials
N2  - We present a cluster model to describe the localization of hot charge carriers on the Si(111)-7 x 7 surface, which leads to (nonlocal) desorption of chlorobenzene molecules in scanning tunneling microscope (STM) manipulation experiments. The localized charge carriers are modeled by a small cluster. By means of quantum chemical calculations, this cluster model explains many experimental findings from STM manipulation. We show that the negative charge is mainly localized in the surface, while the positive one also resides on the molecule. Both resonances boost desorption: In the negative resonance the adatom is elevated; in the positive one the chemisorption bond between the silicon surface adatom and chlorobenzene is broken. We find normal modes promoting desorption matching experimental low-temperature activation energies for electron-and hole-induced desorption.
Y1  - 2017
U6  - https://doi.org/10.1103/PhysRevMaterials.1.026001
SN  - 2475-9953
VL  - 1
IS  - 2
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Utecht, Manuel Martin
A1  - Pan, Tianluo
A1  - Klamroth, Tillmann
A1  - Palmer, Richard E.
T1  - Quantum chemical cluster models for chemi- and physisorption of chlorobenzene on Si(111)-7x7
JF  - The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment & general theory
N2  - Motivated by recent atomic manipulation experiments, we report quantum chemical calculations for chemi- and physisorption minima of chlorobenzene on the Si(111)-7x7 surface. A density functional theory cluster approach is applied, using the B3LYP hybrid functional alongside Grimme's empirical dispersion corrections (D3). We were able to identify chemisorption sites of binding energies of 1.6 eV and physisorption energies of 0.6 eV, both in encouraging agreement with the trend of experimental data. The cluster approach opens up the possibility of a first-principles based dynamical description of STM manipulation experiments on this system, the interpretation of which involves both the chemi- and physisorbed states. However, we found that special care has to be taken regarding the choice of clusters, basis sets, and the evaluation of the dispersion corrections.
Y1  - 2014
U6  - https://doi.org/10.1021/jp504208d
SN  - 1089-5639
VL  - 118
IS  - 33
SP  - 6699
EP  - 6704
PB  - American Chemical Society
CY  - Washington
ER  -