The DL_POLY Classic Molecular Simulation Package

W. Smith

General Information

DL_POLY Classic is a general purpose molecular dynamics simulation package developed at Daresbury Laboratory by W. Smith, T.R. Forester and I.T. Todorov. It is based on the package DL_POLY_2, which was originally developed by the former Computational Chemistry Group at Daresbury Laboratory under the auspices of the EPSRC, for the EPSRC's Collaborative Computational Project for the Computer Simulation of Condensed Phases (CCP5).

DL_POLY Classic can be executed as a serial or parallel application. The code achieves parallelisation using the Replicated Data strategy, which is suitable for homogeneous, distributed-memory, parallel computers. The code is useful for simulations of up to 30,000 atoms with good parallel performance on up to 100 processors, though in some circumstances it can exceed or fail to reach these limits.

Example: DL_POLY_C simulation of DNA in water

The copyright to the software is the property of the Science & Technology Facilities Council (STFC) and the code is made available under the BSD Licence, which permits open access to the source. No registration is required to obtain the software and no support of any kind is offered or implied. Advice on using all DL_POLY packages may be obtained from the DL_POLY mailing list. A full description of DL_POLY Classic may be obtained from the DL_POLY Classic User Manual (PDF).

Example: DL_POLY_C simulation of an alkali silicate glass


Important DL_POLY Classic is distinct from the package known as DL_POLY, which is also available from Daresbury Laboratory as DL_POLY_4. The DL_POLY Classic licence does not apply to DL_POLY_4.

Download instructions

The DL_POLY Classic source code is obtained from gitlab.com as follows:

  1. Access gitlab.com  with a browser.
  2. Select dl_poly
  3. Clock on Tags (Line under the tiltle)
  4. Download the release you are after.
  5. You now have a copy of the DL_POLY Classic software.

Notice that on gitlab.com also has all the data for the DL_POLY Classic test cases that you can download in the same manner. The files have names TESTnn.tar.gz, where nn is a two-digit number.

You can unpack the software as follows:

gunzip dl_class_1.x.tar.gz
tar -xf dl_class_1.x.tar

This will create the dl_class_1.x directory, after which you may delete the dl_class_1.x.tar file to save disc space.

Note:It is recommended that you download the test cases into the dl_class_1.x/data directory and unpack the files there.



A Graphical User Interface (GUI) is available for DL_POLY Classic, based on the Java language from Sun Microsystems. Please see the Java GUI Manual (PDF) for a detailed description.

The Book "Elements of Molecular Dynamics"

"Elements of Molecular Dynamics" is a free book associaterd with the DL_POLY package. Written by W. Smith, a long-time developer of DL_POLY, it provides an introduction to the subject of molecular dynamics and outlines many of the techniques implemented in the DL_POLY programs.

The book can be obtained as a PDF file from the DL_POLY Classic Project on gitlab.com here.

To help improve future releases, comments on the book's content, clarity and errors are invited. Please visit the approved form here.

For more information about DL_POLY_C please contact Prof. William Smith.


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