Michael N. Burnett and Carroll K. Johnson

Chemical Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6197 USA.

The third revision of the Oak Ridge Thermal Ellipsoid Plot Program, ORTEP-III, is now available. The program, including source code, precompiled versions for DOS and Macintosh personal computers, the complete user manual as a downloadable Postscript file, online documentation, examples, and helper programs, is available on the World Wide Web at http://www.ornl.gov/ortep/ortep.html. The program may also be obtained via anonymous ftp from ftp.ornl.gov in the directory /pub/ortep. All inquiries, comments, questions, problems, suggestions, etc. should be sent to ortep@ornl.gov.

This update to ORTEP was undertaken to incorporate some of the advances in computing and printing technologies made since the previous release. Built into the code are drivers to produce Postscript and HPGL/2 files of the ORTEP illustrations. These files may be printed on a variety of printers and plotters and may be imported into a number of other computer applications. Also, ORTEP-III includes a screen driver built around the free graphics library PGPLOT* that permits the user to see the illustration on the screen before producing a hard copy.

Changes and new features in ORTEP-III include: number of input atoms increased from 166 to 500, number of symmetry operators increased from 48 to 96, the ability to enter symmetry operators using the format provided in the International Tables, lower case letters added for labeling, color, atom "features" to make selection of atoms more flexible, an interactive line editor for making changes to the input file without leaving the program, and the ability to produce critical net illustrations (as described elsewhere).

*Information about PGPLOT may be found on the World Wide Web at http://astro.caltech.edu/~tjp/pgplot or via e-mail to tjp@astro.caltech.edu.

Research sponsored by the Laboratory Directed Research and Development Program of the Oak Ridge National Laboratory, managed by Lockheed Martin Energy Research Corp. for the U.S. Department of Energy under Contract No. DE-AC05-96OR22464.