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Create your own material
Unlike CIF, cell is much simpler format and, therefore, you can easily read, create and modify your materials.
File specification
General file specification is quite simple:
- file extension is expected to be '.cell'
- lines beginning with '#' or '%' are considered comments
- white characters between lines or individual numbers are ommited
Material specification
The material is expected to be defined using a unit cell. Its parameters should be written at separate lines as follows:
- lattice parameter a [nm]
- lattice parameter b [nm]
- lattice parameter c [nm]
- lattice angle alpha [deg]
- lattice angle beta [deg]
- lattice angle gamma [deg]
- material structure ('HCP', 'FCC', 'BCC', Diamond') or by fractional Miller indices of individual atoms in the unit cell written as decimal numbers or fractions
- in case of Miller indices, one atom must have coordinates [0 0 0]
- if there is no atom in [0 0 0] coordinates, all atoms are automatically shifted to fulfill this condition
- atomic numbers - either one number if they are all the same for unit cell atoms, or space-separated values - one per each previously stated atomic position
Examples
File 'Mg HCP.cell' describing Mg HCP unit cell:
# Mg HCP
# Lattice parameters - a, b, c [nm]
0.321
0.321
0.521
# Lattice angles - alpha, beta, gamma [deg]
90
90
120
# Structure
HCP
# Element
12
# Lattice parameters - a, b, c [nm]
0.321
0.321
0.521
# Lattice angles - alpha, beta, gamma [deg]
90
90
120
# Structure
HCP
# Element
12
File 'GaAs.cell' describing unit cell of GaAs compound:
# Lattice parameters - a, b, c [nm]
0.565
0.565
0.565
# Lattice angles - alpha, beta, gamma [deg]
90
90
90
# Positions of atoms in unit cell
[0 0 0]
[0 1/2 1/2]
[1/2 0 1/2]
[1/2 1/2 0]
[1/4 1/4 1/4]
[3/4 3/4 1/4]
[1/4 3/4 3/4]
[3/4 1/4 3/4]
# Element
31 31 31 31 33 33 33 33
0.565
0.565
0.565
# Lattice angles - alpha, beta, gamma [deg]
90
90
90
# Positions of atoms in unit cell
[0 0 0]
[0 1/2 1/2]
[1/2 0 1/2]
[1/2 1/2 0]
[1/4 1/4 1/4]
[3/4 3/4 1/4]
[1/4 3/4 3/4]
[3/4 1/4 3/4]
# Element
31 31 31 31 33 33 33 33
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