Fitting dozens of coordinates by LEED: automated determination of complex surface structures

1993 ◽  
Vol 287-288 ◽  
pp. 428-431 ◽  
Author(s):  
M.A. Van Hove ◽  
W. Moritz ◽  
H. Over ◽  
P.J. Rous ◽  
A. Wander ◽  
...  
Keyword(s):  
Complex Surface ◽  
Surface Structures ◽  
Automated Determination

Fitting dozens of coordinates by LEED: automated determination of complex surface structures

1993 ◽  
Vol 287-288 ◽  
pp. A394
Author(s):  
M.A. Van Hove ◽  
W. Moritz ◽  
H. Over ◽  
P.J. Rous ◽  
A. Wander ◽  
...  
Keyword(s):  
Complex Surface ◽  
Surface Structures ◽  
Automated Determination

scholarly journals Automated determination of complex surface structures by LEED

1993 ◽  
Vol 19 (3-6) ◽  
pp. 191-229 ◽  
Author(s):  
M.A. Van Hove ◽  
W. Moritz ◽  
H. Over ◽  
P.J. Rous ◽  
A. Wander ◽  
...  
Keyword(s):  
Complex Surface ◽  
Surface Structures ◽  
Automated Determination

DETERMINATION OF COMPLEX SURFACE STRUCTURES WITH LEED

1997 ◽  
Vol 04 (03) ◽  
pp. 479-487 ◽  
Author(s):  
M. A. VAN HOVE
Keyword(s):  
Complex Surface ◽  
Surface Structures ◽  
Considerable Progress ◽  
Structural Determination ◽  
Experimental Dataset ◽  
The One ◽  
Correct Structure

The evolution of the complexity of structural determination attainable with LEED is reviewed. Considerable progress in methodologies and computers has enabled structures as complex as Cu(100) + (4 × 4)- 10Li to be solved in terms of 18 fit parameters. The Si(111)-(7 × 7) structure could now be refined in terms of 100-or-so fit parameters, if a large-enough experimental dataset were available. Big challenges remain: finding a direct or quick way to identify the one qualitatively correct structure; and, to a lesser degree, providing the required size of the experimental dataset.

COMPLETION OF THE DETERMINATION OF COMPLEX SURFACE STRUCTURES FORMED ON LOW-INDEX PLANES OF COPPER SINGLE CRYSTAL BY Li DEPOSITION: Cu(110)-(4×1)-3Li

1997 ◽  
Vol 04 (06) ◽  
pp. 1221-1226 ◽  
Author(s):  
SEIGI MIZUNO ◽  
HONG JIANG ◽  
HIROSHI TOCHIHARA
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
Room Temperature ◽  
Complex Surface ◽  
Low Energy ◽  
Surface Structures ◽  
Copper Single Crystal ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron

With increasing Li coverage on Cu(110), (n×1)(4≤n≤8) structures follow the (1×2) missing-row structure at room temperature. We determine the (4×1) structure by a dynamical low-energy electron diffraction (LEED) analysis with symmetrized automated tensor LEED. This completes the solution of the complex surface structures formed on low-index planes of copper single crystal by Li deposition. Every fourth Cu row in the [001] direction is substituted by Li atoms and the remaining Cu rows are covered by Li adatoms. Features of this structure, denoted as Cu (110)-(4×1)-3 Li , are very similar to those of the previously determined Cu (001)-(3×3)-5 Li , Cu (001)-(4×4)-10 Li and Cu (111)-(2×2)-3 Li structures.

Ultrathin Platinum Crystal Surface Structures

1985 ◽  
Vol 43 ◽  
pp. 394-395
Author(s):  
R. L. Hines
Keyword(s):  
Crystal Surface ◽  
Surface Structures ◽  
Platinum Surface ◽  
Platinum Surfaces ◽  
Resolution Level ◽  
Experimental Facilities ◽  
Carbon Backing ◽  
Mesh Grid ◽  
Atom Layer

The importance of atom layer terraces or steps on platinum surfaces used for catalysis as discussed by Somorjai justifies an extensive investigation of the structure of platinum surfaces through electron microscopy at the atomic resolution level. Experimental and theoretical difficulties complicate the quantitative determination of platinum surface structures but qualitative observation of surface structures on platinum crystals is now possible with good experimental facilities.Ultrathin platinum crystals with nominal 111 orientation are prepared using the procedure reported by Hines without the application of a carbon backing layer. Platinum films with thicknesses of about ten atom layers are strong enough so that they can be mounted on grids to provide ultrathin platinum crystals for examination of surface structure. Crystals as thin as possible are desired to minimize the theoretical difficulties in analyzing image contrast to determine structure. With the current preparation procedures the crystals frequently cover complete openings on a 400 mesh grid.

An Automated Procedure for the Determination of Ammonia in Tobacco

1972 ◽  
Vol 6 (4) ◽  
Author(s):  
P.F. Collins ◽  
W.W. Lawrence ◽  
J.F. Williams
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Distillation Method ◽  
Relative Standard ◽  
Tobacco Sample ◽  
Automated Determination

AbstractA procedure for the automated determination of ammonia in tobacco has been developed. Ammonia is extracted from the ground tobacco sample with water and is determined with a Technicon Auto Analyser system which employs separation of the ammonia through volatilization followed by colourimetry using the phenate-hypochlorite reaction. The procedure has been applied to a variety of tobaccos containing from 0.02 to 0.5 % ammonia with an overall relative standard deviation of 2 %. The accuracy of the procedure as judged by recovery tests and by comparison to a manual distillation method is considered adequate

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