exercises:2015_ethz_mmm:surface_cu
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TO USE THE FUNCTION LIBRARY (VERSION UP TO DATE) IN THE INTERACTIVE SHELL:
you@eulerX ~$ module load courses mmm ; mmm-init
Generation of slab with high symmetry surfaces
Surface energies of Copper high-symmetry surfaces
In this exercise we will compute the surface energies of Cu using the EAM potential. As a reference, we report the table from the Gross book:
- Copy the files from from the wiki: exercise_3.1.zip (all inputs are commented) into a new directory
- Run the optimizations 100.inp, 110.inp, 111.inp —- look at the corresponding initial coordinate files 100.xyz, 110.xyz, 111.xyz.
- In vmd, you can also open a console, and give the command pbc set { a b c 90 90 90 } where a, b, c can be extracted from the cp2k input file. Then you can make several periodic copies for visualization.
- Compute the three surface energies: you need to compute the area, subtract bulk contribution, take care of the units.
- In the class we will learn how to compute the Wulff crystal from these three numbers.
- Basically, you should edit the input file “DP”, replacing the column beginning with “PUT_HERE_THE_XXX_SURFACE_ENERGY” with quantities that are proportional to the three surface free energies (see Wulff theorem). Note that for the {100} and {110} surfaces you need to edit TWO lines each, since the z direction is treated differently in this program.
- At this point, you run the program with the command ./sowos.v02.00.02.x
- There will be many output files. Important are
- * the atomistic model out.atomistic-inside-gnuplot.xyz which will contain many atoms if you chose a proportionality constant in the file DP which is too large. If you appropriately modify it (how?) you can have a xyz file to be opened in vmd.
- * the out.plot-gnuplot.plt file. If you launch gnuplot, then “load “out.plot-gnuplot.plt” a plot of the crystal will be shown. To have it more or less to scale in all directions: set xrange [-80:80];set yrange [-80:80]; set view equal xyz; replot
- * you can rotate with the mouse!
Assignment: use the cluster generated with SOWOS as an input configuration for a cluster optimization with cp2k. Comment on the final geometry. BEWARE OF THE CELL! It is not a periodic system!
documentation on SOWOS can be found at the web site of Daniele Scopece
exercises/2015_ethz_mmm/surface_cu.1425608305.txt.gz · Last modified: 2020/08/21 10:14 (external edit)