# Open SourceMolecular Dynamics

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exercises:2016_uzh_cmest:bulk_modulus_calculation

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 exercises:2016_uzh_cmest:bulk_modulus_calculation [2016/10/29 19:44]tmueller exercises:2016_uzh_cmest:bulk_modulus_calculation [2016/10/30 11:25] (current)tmueller Both sides previous revision Previous revision 2016/10/30 11:25 tmueller 2016/10/29 19:44 tmueller 2016/10/29 19:43 tmueller 2016/10/29 19:36 tmueller created 2016/10/30 11:25 tmueller 2016/10/29 19:44 tmueller 2016/10/29 19:43 tmueller 2016/10/29 19:36 tmueller created Line 3: Line 3: Many times when doing an analysis of a (novel) material, you have to validate your model against values from real experiments. One of those values is the bulk modulus of a material which we are going to calculate for bulk silicon. Many times when doing an analysis of a (novel) material, you have to validate your model against values from real experiments. One of those values is the bulk modulus of a material which we are going to calculate for bulk silicon. - If you are looking at a crystal with a well known structure, the simulation study gets particularly easy since you can specify the atomic coordinates in terms of an irreducible cell: + If you are looking at a crystal with a well known structure, the simulation study gets particularly easy since you can specify the atomic coordinates in terms of an irreducible cell (note the ''​SCALED''​ keyword in the ''&​COORD''​ section): ​ Line 55: Line 55: ​ - By scaling the lattice constant (for example between $0.97 \cdot a$ and $1.1 \cdot a$) you can now run the simulation for different volumes and get a volume-energy curve. ​By fitting ​this curve to the Birch–Murnaghan equation of state you can then recover the bulk modulus $B_0$. + * By scaling the lattice constant (for example between $0.97 \cdot a$ and $1.1 \cdot a$) you can now run the simulation for different volumes and get a volume-energy curve. ​You may want to use and adapt the script from the [[calculation_pbc|previous exercise]] + * Fit this curve to the Birch–Murnaghan equation of state to recover the bulk modulus $B_0$