Desorption induced by low energy charge carriers on Si(111)‐7 × 7: First principles molecular dynamics for benzene derivates

Abstract

We use clusters for the modeling of local ion resonances caused by low energy charge carriers in STM‐induced desorption of benzene derivates from Si(111)‐7 × 7. We perform Born–Oppenheimer molecular dynamics for the charged systems assuming vertical transitions to the charged states at zero temperature, to rationalize the low temperature activation energies, which are found in experiment for chlorobenzene. Our calculations suggest very similar low temperature activation energies for toluene and benzene. For the cationic resonance transitions to physisorption are found even at 0 K, while the anion remains chemisorbed during the propagations. Further, we also extend our previous static quantum chemical investigations to toluene and benzene. In addition, an in depth analysis of the ionization potentials and electron affinities, which are used to estimate resonance energies, is given. © 2018 Wiley Periodicals, Inc.

Nonlocal STM Manipulation of Chlorobenzene on Si(111)-7 × 7: Potentials, Kinetics, and First-Principles Molecular Dynamics Calculations for Open Systems

“…i.e., we fit to the Arrhenius law, to extract the activation energy E A and the preexponential factor A. Molecular Dynamics. We use the ADMP 40,41 (Atom centered Density Matrix Propagation molecular dynamics model) within the Gaussian09 program 28 for the AIMD calculations with a time step Δt of 0.5 fs as in ref 22. In each time step, a full SCF calculation is performed.…”

“…Further, the ΔE values for discrete τ res computed for the ensembles at 300 K roughly follow the trends shown at 0 K. Here, the ΔE value for 0 K is mostly near the upper edge of the range found for 300 K. Thus, we are confident that the chosen discrete residence times are sufficient to sample the dynamics in the resonance state. This dynamics is characterized by the breaking of the bond to the silicon adatom for the cation (see the animation given in the Supporting Information, page S8), while for the anion, the adatom elevation is the main effect (see ref 22 for further details). The minimum energy gain ΔE needed to desorb is indicated by the horizontal dashed line.…”

“…In recent years, we have established cluster models for the chemisorbed and physisorbed molecules and the quantum chemical modeling of localized charge carriers. − In ref , we introduced cluster models for the description of localized charges, which approximately reproduced the observed thresholds in nonlocal desorption of chemisorbed molecules at room temperature, i.e., 1.4 V for electrons and −1.2 V for holes . Experiments at variable temperatures , indicated a thermally assisted nonlocal desorption mechanism at low temperatures.…”

Exploring the Dual Characteristics of CH3OH Adsorption to Metal Atomic Structures on Si (111)-7 × 7 Surface

“…As an important substrate material, Si (111)-7 × 7 is a surface with a well-established atomic and electronic structure [ 1 ]. Its epitaxial growth is of great significance to the study of surface characteristics.…”

Metal Deposition Induced by the Step Region of Si (111)-(7 × 7) Surface

“…Among them, those on the top layer are called corner sites and center sites, and those on the rest layer are called rest sites. Its atomic structure growth is significant to the study of metal deposition [7,8]. However, despite such theoretical and functional values, there are a very limited number of application cases that can exactly reach the atomic level.…”