scholarly journals Calcium and fluorine signals in HS-LEIS for CaF2(111) and powder—Quantification of atomic surface concentrations using LiF(001), Ca, and Cu references

2020 ◽  
Vol 27 (2) ◽  
pp. 024201
Author(s):  
Stanislav Průša ◽  
Pavel Bábík ◽  
Jindřich Mach ◽  
Tomáš Strapko ◽  
Tomáš Šikola ◽  
...  
Keyword(s):  
Author(s):  
H. Bethge

Besides the atomic surface structure, diverging in special cases with respect to the bulk structure, the real structure of a surface Is determined by the step structure. Using the decoration technique /1/ it is possible to image step structures having step heights down to a single lattice plane distance electron-microscopically. For a number of problems the knowledge of the monatomic step structures is important, because numerous problems of surface physics are directly connected with processes taking place at these steps, e.g. crystal growth or evaporation, sorption and nucleatlon as initial stage of overgrowth of thin films.To demonstrate the decoration technique by means of evaporation of heavy metals Fig. 1 from our former investigations shows the monatomic step structure of an evaporated NaCI crystal. of special Importance Is the detection of the movement of steps during the growth or evaporation of a crystal. From the velocity of a step fundamental quantities for the molecular processes can be determined, e.g. the mean free diffusion path of molecules.


Author(s):  
V. Castano ◽  
W. Krakow

In non-UHV microscope environments atomic surface structure has been observed for flat-on for various orientations of Au thin films and edge-on for columns of atoms in small particles. The problem of oxidation of surfaces has only recently been reported from the point of view of high resolution microscopy revealing surface reconstructions for the Ag2O system. A natural extension of these initial oxidation studies is to explore other materials areas which are technologically more significant such as that of Cu2O, which will now be described.


Author(s):  
Jan-Olle Malm ◽  
Jan-Olov Bovin

Understanding of catalytic processes requires detailed knowledge of the catalyst. As heterogeneous catalysis is a surface phenomena the understanding of the atomic surface structure of both the active material and the support material is of utmost importance. This work is a high resolution electron microscopy (HREM) study of different phases found in a used automobile catalytic converter.The high resolution micrographs were obtained with a JEM-4000EX working with a structural resolution better than 0.17 nm and equipped with a Gatan 622 TV-camera with an image intensifier. Some work (e.g. EDS-analysis and diffraction) was done with a JEM-2000FX equipped with a Link AN10000 EDX spectrometer. The catalytic converter in this study has been used under normal driving conditions for several years and has also been poisoned by using leaded fuel. To prepare the sample, parts of the monolith were crushed, dispersed in methanol and a drop of the dispersion was placed on the holey carbon grid.


2019 ◽  
Author(s):  
Seoin Back ◽  
Junwoong Yoon ◽  
Nianhan Tian ◽  
Wen Zhong ◽  
Kevin Tran ◽  
...  

We present an application of deep-learning convolutional neural network of atomic surface structures using atomic and Voronoi polyhedra-based neighbor information to predict adsorbate binding energies for the application in catalysis.


2011 ◽  
Vol 471 (21-22) ◽  
pp. 698-700 ◽  
Author(s):  
A. Sugimoto ◽  
R. Ukita ◽  
T. Ekino ◽  
Y. Harada ◽  
T. Furukawa ◽  
...  

Nanoscale ◽  
2017 ◽  
Vol 9 (32) ◽  
pp. 11410-11417 ◽  
Author(s):  
D. Zhang ◽  
M. J. Quayle ◽  
G. Petersson ◽  
J. R. van Ommen ◽  
S. Folestad

Few atomic surface layers via atomic layer deposition under near ambient conditions significantly altered dissolution and dispersion of pharmaceutical particles.


2014 ◽  
Vol 5 ◽  
pp. 202-209 ◽  
Author(s):  
Christian Wagner ◽  
Norman Fournier ◽  
F Stefan Tautz ◽  
Ruslan Temirov

Scanning probe microscopy (SPM) plays an important role in the investigation of molecular adsorption. The possibility to probe the molecule–surface interaction while tuning its strength through SPM tip-induced single-molecule manipulation has particularly promising potential to yield new insights. We recently reported experiments, in which 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) molecules were lifted with a qPlus-sensor and analyzed these experiments by using force-field simulations. Irrespective of the good agreement between the experiment and those simulations, systematic inconsistencies remained that we attribute to effects omitted from the initial model. Here we develop a more realistic simulation of single-molecule manipulation by non-contact AFM that includes the atomic surface corrugation, the tip elasticity, and the tip oscillation amplitude. In short, we simulate a full tip oscillation cycle at each step of the manipulation process and calculate the frequency shift by solving the equation of motion of the tip. The new model correctly reproduces previously unexplained key features of the experiment, and facilitates a better understanding of the mechanics of single-molecular junctions. Our simulations reveal that the surface corrugation adds a positive frequency shift to the measurement that generates an apparent repulsive force. Furthermore, we demonstrate that the scatter observed in the experimental data points is related to the sliding of the molecule across the surface.


ACS Catalysis ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 4006-4014 ◽  
Author(s):  
Ezra L. Clark ◽  
Stefan Ringe ◽  
Michael Tang ◽  
Amber Walton ◽  
Christopher Hahn ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document