exercises:2017_uzh_cmest:adsorption
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exercises:2017_uzh_cmest:adsorption [2017/11/06 15:21] – tmueller | exercises:2017_uzh_cmest:adsorption [2017/11/07 10:19] – [Lattice constant optimization] tmueller | ||
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===== Lattice constant optimization ===== | ===== Lattice constant optimization ===== | ||
- | As you have seen in earlier exercises, the actual energy -- and therefore also the stress tensor -- depends on many parameters, like the selected functional. This means that geometrical parameters like the lattice constant may also vary and therefore | + | As you have seen in earlier exercises, the actual energy -- and therefore also the stress tensor -- depends on many parameters, like the selected functional. This means that geometrical parameters like the lattice constant may also vary and therefore |
What we are using to determine the center volume (the volume for which the energy is minimal) is the Birch–Murnaghan equation of state (to be precise: the BM equation integrated over pressure), which links the energy and the volume using the minimal energy $E_0$, the center volume $V_0$, the bulk modulus $B_0$ and its derivative $B_1$: | What we are using to determine the center volume (the volume for which the energy is minimal) is the Birch–Murnaghan equation of state (to be precise: the BM equation integrated over pressure), which links the energy and the volume using the minimal energy $E_0$, the center volume $V_0$, the bulk modulus $B_0$ and its derivative $B_1$: | ||
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\end{align*} | \end{align*} | ||
- | Use the following input file as a starting point, and an adapted version of the script you documented in a [[exercises: | + | Use the following input file as a starting point, and an adapted version of the script you documented in a [[exercises: |
Extract the energies and fit $E_0$, $V_0$, $B_0$, $B_1$ using the Birch–Murnaghan EOS and using the new $V0$ determine the lattice constant. | Extract the energies and fit $E_0$, $V_0$, $B_0$, $B_1$ using the Birch–Murnaghan EOS and using the new $V0$ determine the lattice constant. | ||
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< | < | ||
a=3.54 | a=3.54 | ||
- | sed -e "s/2.4612/$a/g" graphene.inp > " | + | sed -e "s|2.4612|$a|g" graphene.inp > " |
</ | </ | ||
</ | </ | ||
- | =====CO adsorption on graphene===== | + | ===== CO adsorption on graphene ===== |
+ | |||
+ | Adsorb one CO molecule on the graphene 6X6X1 supercell at the top(T), bridge(B) and center(C) sites (see the paper for the definitions) and optimize the geometry. | ||
+ | You need change the '' | ||
+ | |||
+ | <note tip> | ||
+ | You can get a 6x6x1 unit cell with absolute coordinates by using '' | ||
+ | |||
+ | |||
+ | |||
+ | < | ||
+ | |||
+ | </ | ||
+ | </ | ||
- | Adsorb one CO molecule on the graphene 6X6X1 supercell at the top(T), bridge(B) and center(C) sites and optimize the geometry. | ||
- | You need change the RUN_TYPE to GEO_OPT and also specify the coordinate by yourself. One can get 6x6x1 unit cell by using MULTIPLE_UNIT_CELL which was mentioned in previous exercises. | ||
< | < | ||
&GLOBAL | &GLOBAL |
exercises/2017_uzh_cmest/adsorption.txt · Last modified: 2020/08/21 10:15 by 127.0.0.1