The CASTEP TS Confirmation dialog allows you to set up and display the parameters that control the simulation in a CASTEP TS Confirmation task.
Quality: Set the geometry optimization convergence thresholds for energy change, maximum force, and maximum displacement between optimization cycles. The optimization will stop when the energy convergence is satisfied along with either the displacement or gradient criteria.
Four sets of convergence thresholds are available:
The values of the convergence thresholds in each set are given in the table below:
|Energy (eV/atom)||1 × 10-4||2 × 10-5||1 × 10-5||5 × 10-6|
|Max. force (eV/Å)||0.5||0.1||0.05||0.02|
|Max. displacement (Å)||0.05||0.005||0.004||0.003|
Alternatively, thresholds can be specified independently for Energy, Max. force, and Max. displacement. If you enter your own values for any of these settings, the Quality is displayed as Customized on both the CASTEP TS Confirmation dialog and the Setup tab of the CASTEP Calculation dialog.
When the main quality is set to Express the transition state confirmation quality is also set to Express. In this case the energy tolerance will be displayed in eV/cell rather than eV/atom, the default value is 0.002 eV/cell.
Energy: Specify the convergence threshold for the maximum energy change, in eV/atom, during the geometry optimization. The units are eV/cell if the Quality is set to Express.
Max. force: Specify the convergence threshold for the maximum force, in eV/Å, during the geometry optimization.
Max. displacement: Specify the convergence threshold for the maximum displacement, in Å, during the geometry optimization.
Altering the value of any threshold is allowed and results in the Quality being set to Customized.
Max. images: The number of intermediate NEB images used during the transition state confirmation.
|Menu||Modules | CASTEP | Calculation | Setup | More...|
|Toolbar||| Calculation | Setup | More...|
Setup tab - CASTEP Calculation dialog
CASTEP Geometry Optimization dialog
CASTEP Transition State Search dialog