Depending on the type of calculation performed, a CASTEP run may produce a trajectory document and one or more chart documents. These documents have a special association with each other because each of the points on the graphs correspond to a frame in the trajectory.
CASTEP produces a trajectory (
.xtd) file whenever you run a geometry optimization, molecular dynamics or elastic constants
calculation, or a transition state search. In all cases, a history of the optimization is returned in a file called
Trajectory.xtd, where <name> is the name used for the job description on the
Job Control tab of the CASTEP Calculation dialog.
When you run a geometry optimization, two chart documents are generated:
<name> Energies.xcd: Contains a plot of total energy vs. frame for all steps of the calculation
<name> Convergence.xcd: Contains three (possibly four) plots that describe the degree of convergence of the optimization as a function of frame:
Because these values span several orders of magnitude, the data are plotted on a log10 scale.
Similar charts are produced for each structure in an elastic constants calculation.
When you run a transition state search, a single chart containing a graph of energy vs. reaction coordinate for each step of the calculation,
<name> TSSearch.xcd, is generated. This includes an individual graph for each LST or QST 'uphill' cycle as well as a
graph for each conjugate gradient minimization. The CASTEP Transition State Search task topic contains more details.
When you run a molecular dynamics simulation, either two or three chart documents are generated:
<name> Constant.xcd: Contains a plot of the constant of motion vs. simulation time
<name> Temperature.xcd: Contains a plot of temperature vs. simulation time
<name> Pressure.xcd: Contains a plot of pressure vs. simulation time (only produced by the NPH or NPT ensemble)
Trajectory files can be animated using the controls on the Animation toolbar.
If you have access to the Forcite module, you may find some of its dynamics, statistical, and structural analysis features useful for analyzing trajectories. Refer to the Using Forcite Analysis topic for details.
When you run CASTEP via the Materials Studio interface, the creation and display of these trajectories and charts is automatic. If you selected Automatically view output on the CASTEP Job Control Options dialog, the graphs will be displayed automatically on completion of the run. If you selected Update graphs on the CASTEP Job Control Options dialog, these graphs will be displayed and updated with intermediate results throughout the course of the calculation.
To create charts from output files generated by a standalone calculation
.castepfile is the currently active document.
If you used the Materials Studio interface to set up and launch your job, you can regenerate the chart documents by following a similar procedure.
To regenerate charts
.castepfile and make it the currently active document.
You can use the controls on the Animation toolbar to animate the trajectory, stepping through each of the frames of the document. If the chart is open during the animation, the point corresponding to the active frame will be highlighted.
Alternatively, you can use Chart Viewer point selection to display the trajectory frames of the points you select from the chart document.
To display a trajectory frame for a point on a chart document
To make it easier to see the chart and trajectory documents, close all the other documents and then maximize the sizes of these two documents by selecting Window | Tile Vertically from the menu bar.
Analyzing CASTEP results
Visualizing volumetric data
Displaying band structure charts
Displaying density of states charts
Displaying optical properties
Using point selection to view related data