ChemApp "light" README
Notes on the usage of ChemApp light with Unix®

These release notes contain information on

  1. how to install ChemApp,
  2. how to use ChemApp light with Unix,
  3. what example programs and example data-files are available,
  4. notes for users of ChemSage V3.x,
  5. how to sign up for e-mail support,
  6. how to report a problem or bug,
  7. how to join our GTT-News newsletter mailing list,
  8. and how to contact us.

Please read this file and the file version.txt and license.txt before using ChemApp, and feel free to contact us any time if you need any further information.

You should also take a look at the ChemApp FAQ, which is at FAQ. It answers a lot of standard questions about ChemApp and ChemApp light and should especially be consulted before contacting our support.

Another must read for ChemApp developers is the chapter ChemApp best practises in the ChemApp Programmer's Manual (added for Edition 3.6). Before you contact our support with specific questions relating to your code, please make sure your code implements the ChemApp best practises.

  1. To install your version of ChemApp light, copy the distribution archive to the directory of your choice.

    How to uncompress the distribution archive depends on the type of archive you received. In the following examples, substitute <distribution> for the actual name of the distribution.

    • .tar.gz archive

      Uncompress with GNU tar:

      tar -xvzf <distribution>.tar.gz

      Note that your version of GNU tar might be called gtar.

    • .tar.Z archive

      Use uncompress and pipe through tar:

      uncompress -c <distribution>.tar.Z | tar xvf -

      Or, if you have GNU tar available:

      tar -xvZf <distribution>.tar.Z

      Note that your version of GNU tar might be called gtar.

    • .tar archive

      Uncompress using tar:

      tar -xvf <distribution>.tar

    The installation program creates a directory tree for ChemApp light containing all necessary files: The ChemApp library itself, various text and HTML files, the example programs and application notes for the languages supported by this distribution, and the example data-files.

    This distribution does NOT include the documentation for ChemApp light. The documentation for ChemApp light comes as a set of HTML files to be viewed with your web browser, and is available for download in a separate archive, also from the ChemApp light web page.

  2. This version of ChemApp has been compiled for a Unix system. For the exact target platform, see the file 'version.txt'.

    If you find that this version of ChemApp does not work on your machine, for instance due to processor or OS version differences, please contact us.

    On most Unix systems, both FORTRAN and C can be used with this version of ChemApp light to write application programs.

    When using FORTRAN, you need to link your application program against libLChemApp.a.

    When using C, you need to link against both libLChemApp.a and libChemAppC.a. Your application program must also include the file cacint.h.

    Please consult the files 'c-notes.txt' and 'f-notes.txt', which provide programming notes relating to C/C++ and FORTRAN. The C/ and FORTRAN/ subdirectories contain sample Makefiles for these languages. The program cademo1 mentioned below is available in both FORTRAN and C.

  3. A program named cademo1 is included with the distribution archive that demonstrates the use of each of the ChemApp functions. You can also use it to verify that you are compiling and linking correctly. When running the compiled program, compare its results with the results in the file cademo1.rst. They should be identical, except for formatting issues.

    The online documentation for ChemApp light, available from our web page, contains many more example codes.

    Apart from the thermochemical files cosi.dat (system C-O-Si) and subl-ex.dat (simplified system Co-Cr-Fe), which are used by the example program cademo1, this distribution also contains several other thermochemical data-files. Check the subdirectory dat for these data-files, and the ChemApp light documentation for details.

  4. Note for users of ChemSage V3.x: If you are still using ChemSage V3.x and would like to continue using your existing thermochemical data-files with ChemApp, you will need to convert them to the ChemSage 4.x/ChemApp format with a program called ChemFile. This program can be obtained from GTT-Technologies upon request, in case it is not included in this distribution of ChemApp. Note that users of ChemSage V4.x, FactSage, and earlier versions of ChemApp do not need to convert their data-files.

  5. To receive limited e-mail support for ChemApp light, please register your copy of ChemApp light. Registration is free and can be done in any of the following ways:

  6. We have installed a bug tracking system for ChemApp that allows us to handle bug and problem reports in a quick and flexible fashion. If you have a programming problem with ChemApp that you suspect might be a bug, please use the Bug Report Form at

    Bug Report Form

    There is also a link to this page from the ChemApp web page.

    If you don't have access to the World Wide Web, you can submit your bug reports by e-mail to We prefer the submission of bug reports via the web page though, since filling in the Bug Report Form makes sure we have important information like the ChemApp version number etc. we need to reproduce your problem already.

    If you have any other general or support questions about ChemApp, there is always our support e-mail address:

  7. Join our GTT-News newsletter mailing list: This newsletter is distributed mainly electronically by e-mail, and also posted to our web site ( It contains announcements of new versions of our various software programs, information on new features and enhancements, ongoing projects, new thermochemical data, additions to our web site, seminars, publications, and various other topics. To join, check the GTT-News section on our web site for instructions, or send an e-mail to with the line
    in the mail body.

  8. An up-to-date source of information on ChemApp, its applications, and related topics is "GTT's Technical Thermochemistry Web Page":

    We would like to include a brief description of your projects involving ChemApp on this World Wide Web page too. Please contact Dr. Stephan Petersen ( for details.

UNIX is a registered trademark of X/Open Company Ltd.

If you have any problems or questions regarding ChemApp, please contact:

  Kaiserstrasse 100
  52134 Herzogenrath

Phone: +49-2407-59533 Fax: +49-2407-59661 E-mail: WWW:

GTT-Technologies, 5 June 2003

Copyright (C) GTT-Technologies 1996-2003, Herzogenrath, Germany


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