CASTEP > Tasks in CASTEP > Analyzing CASTEP results > Updating structure

Updating structure

Updating cell parameters and atomic coordinates after Geometry Optimization or a Dynamics run should be the first step in the Analysis process.

Structure updates happen automatically after a CASTEP job is completed and the results files have been downloaded successfully. The description below is, therefore, only relevant for jobs which were run in standalone mode and where the results files were transferred manually, or results files in which the final structure produced by CASTEP has been manually modified and you wish to revert to the unmodified form.

You can update the structure if the chemical composition (the number of atomic species and the number of atoms of each kind) has not been changed since Materials Studio saved the structure in the results folder. After the update, the cell parameters and atom coordinates are set to the values returned by the CASTEP run in the (hidden) binary .check file.

To update the structure

  1. Choose Modules | CASTEP | Analysis from the Materials Studio menu bar.
  2. Select Structure from the list of properties.
  3. Ensure that the 3D model document to be updated is active.
  4. Click the Update button.

An error message is generated if the output .check file is incomplete, or if the chemical composition of the model has been changed.
The Update button is enabled only if the output .check file is present and the active document is the 3D model to be updated.

Creating a trajectory file

A trajectory file, seedname.xtd, is automatically created when a CASTEP job is completed and the results files have been downloaded successfully. The description below is, therefore, only relevant for jobs which were run in standalone mode and where the results files were transferred manually.

The CASTEP server returns a number of ASCII text files to the client PC that can be used to create a trajectory file for either a geometry optimization or a dynamics calculation. This trajectory is saved in a hidden seedname Trajectory.trj file in the results folder.

This file contains complete information on the structure evolution, including changes in the energy, temperature, stress, velocities and forces. Materials Studio does not currently provide tools for analyzing this information. Although, it is possible to animate the trajectory.

To perform statistical analysis of the results or to visualize atomic vectors (forces and velocities) you can use Forcite Analysis.

To create a trajectory

  1. Choose Modules | CASTEP | Analysis from the Materials Studio menu bar.
  2. Select Structure from the list of properties.
  3. Ensure that the current document is either the 3D model in the results folder or the .castep file of the corresponding calculation.
  4. Click the Create button.
See Also:

Structure selection - CASTEP Analysis dialog
Analyzing CASTEP results

Accelrys Materials Studio 8.0 Help: Wednesday, December 17, 2014
Legal Notices