Geometry Optimisation with CASTEP

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Next: The .cell file and Up: Geometry Optimisation with CASTEP Previous: Recipe Inputs There are three principal inputs; the .cell file, the .param file and the pseudopotential library. Subsections ● The .cell file and Pseudopotential libraries ❍ The Size and Shape of the Supercell ❍ The Initial Configuration of the Atoms Within the Supercell ❍ The k-point sampling grid ❍ Cell symmetry ❍ Constraints on the cell size/shape ❍ Constraints on the movement of ions ❍ Atomic masses ❍ The location of the pseudopotential libraries ❍ External pressure that is to be applied to the supercell ● The .param file ❍ General Job Parameters ❍ Basis Set Parameters ❍ Variable Cell Calculations ❍ Electronic Minimisation Parameters 2005-04-04
Next: The Size and Shape Up: Inputs Previous: Inputs The .cell file and Pseudopotential libraries Together these contain all of the information relevent to the material in the supercell. The supercell size and shape and the ionic positions within the supercell must be specified. The other cell parameters can be omitted and defaults will be applied in their place. Beware; it is advisable to specify most cell parameters. For example, the default Monkhorst-Pack (MP) k-point grid is unlikely to be suitable for most geometry optimisation jobs. Subsections ● ● ● ● ● ● ● ● ● The Size and Shape of the Supercell The Initial Configuration of the Atoms Within the Supercell The k-point sampling grid Cell symmetry Constraints on the cell size/shape Constraints on the movement of ions Atomic masses The location of the pseudopotential libraries External pressure that is to be applied to the supercell 2005-04-04
Page 1 and 2: Next: Recipe Geometry Optimisation
Page 3: Next: Inputs Up: Geometry Optimisat
Page 7 and 8: In both cases if [units] are not sp
Page 9 and 10: After the atomic symbol or the atom
Page 11 and 12: KPOINTS_MP_SPACING [units] Where is
Page 13 and 14: 2005-04-04
Page 15 and 16: Next: Atomic masses Up: The .cell f
Page 17 and 18: It is possible to fix the positions
Page 19 and 20: Next: External pressure that is Up:
Page 21 and 22: Next: General Job Parameters Up: In
Page 23 and 24: When a calculation that was stopped
Page 25 and 26: Next: Electronic Minimisation Param
Page 27 and 28: Next: Example - Bulk Silicon Up: Th
Page 29 and 30: the default value is 3 but it must
Page 31 and 32: We must now choose a supercell to e
Page 33 and 34: Next: The .castep file Up: Geometry
Page 35 and 36: 4 -2.14844155E+002 -9.84322032E-003
Page 37 and 38: BFGS: Final Configuration: ========
Page 39 and 40: Next: Other output files Up: Output
Page 41 and 42: Next: A Variable Cell calculation U
Page 43 and 44: arbitrary set of basis set paramete
Page 45 and 46: 3 -2.16474423E+002 2.10512829E-007
Page 47 and 48: Figure 6:A finite vacuum gap may ca
Page 49 and 50: 0.0000000000 0.0000000000 24.503725
Page 51 and 52: thickness We can see that the total
Page 53 and 54: It is interesting to look at the ev
Page 55 and 56:
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Geometry Optimisation with CASTEP

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