Copper crystal
What is copper's crystal structure and how stiff is it?
You ask
What is its crystal structure and how stiff is it?
Wobbl runs
$ wobbl simulate copper "what is its crystal structure and how stiff is it?" \ --no-open
Lattice strain 0 % of 0 %
peak strain energy
0 eV/atom
OK
Bulk modulus 133 GPa, pressure 0 GPa
Checks, numbers and charts
OKFcc copper by EMT: lattice constant 3.590 A, density 9.12 g/cm3, bulk modulus 133 GPa and cohesive energy 3.52 eV per atom. Measured, the lattice constant is 3.610 A.
- Lattice constant
- 3.590 A
- Density
- 9.12 g/cm3
- Bulk modulus
- 133 GPa
- Confidence
- high
- passequation of state
- passreference data
OK. Fcc copper by EMT: lattice constant 3.590 A, density 9.12 g/cm3, bulk modulus 133 GPa and cohesive energy 3.52 eV per atom. Measured, the lattice constant is 3.610 A. Confidence: high. passed equation of state, reference datalattice constant: 3.590 Adensity: 9.12 g/cm3bulk modulus: 133 GPacohesive energy: 3.52 eV/atom Checks: [pass] equation of state: 9 volumes from -17% to +19% around the measured one bracket the minimum, and the Birch-Murnaghan fit misses them by 0.82 meV [pass] reference data: against measurements, lattice constant 3.59 A against 3.61 (0.6% apart); bulk modulus 133 GPa against 137 (2.9% apart); cohesive energy 3.52 eV/atom against 3.49 (0.8% apart) (the largest miss is 0.4 times EMT's typical error) Assumptions: - Wobbl guessed: temperature not given: assumed 25 C (298.15 K). - Wobbl guessed: pressure not given: assumed 1 atm. - fcc copper at 0 K with the measured shape held as the volume changes, by EMT, good to about 1.5% in lattice constant and 20% in bulk modulus. - Zero point motion and thermal expansion are left out, which together make room temperature lattices about 0.5% larger. Images: eos: images/eos.pngReport: report.htmlAbout this example
Wobbl takes fcc copper from its name, picks EMT (the right calculator for a metal) through ASE, and fits an equation of state over nine volumes to get the lattice constant, density, bulk modulus and cohesive energy. Other solids use GFN-FF or xTB instead.
| Result | Value | Measured |
|---|---|---|
| Lattice constant | 3.590 A | 3.61 A |
| Density | 9.12 g/cm3 | |
| Bulk modulus | 133 GPa | 137 GPa |
| Cohesive energy | 3.52 eV per atom | 3.49 eV |
output/playback.json holds the atoms, bonds and frames the viewer plays.
Run it yourself
$ git clone https://github.com/sohan-bhat/wobbl$ cd wobbl/examples/copper-crystal && ./run.shThe part, the script and every output are in examples/copper-crystal on GitHub.