We will discuss the rôle of visualization in atomistic modeling, presenting arguments in favour and discussing reasons why some might find this difficult. Arguments in favour include help in debugging, help in understanding what is happening in the simulation and resultant insights into the physics of the systems. Visualization faciltates discussion with experimental collaborators and presentation.

The MC and MD calculations made in the Computational Physics Group at the Technion will then be described. These include modeling of diamond/graphite systems and aluminium/alumina interfaces, as well as studying defects in copper and vanadium. Some examples of new physics results obtained thru our older visualizations of simulation samples will be given[1].

After discussing problems with the implementation of existing visualization systems for our purposes our new AViz[2] package will be introduced. Our selection of Mesa and the QT GUI as well as the options we have built into AViz will be explained. Examples of AViz' use such as modeling the creation of interstitial defects in diamond, and the behaviour of a 50,000 atom drop of aluminium on an alumina surface will be presented. Some tricks for 3d visualization, such as highlighting atoms with changed coordination numbers and bonds as well as their implementation in AViz will be described.

Visualization of spin systems is also possible with AViz, as is the preparation of animations and movies. A discussion of how we are trying to make our package easy for others to use and how we have solved possible problems with visualization such as cost will also be given. AViz is Open Source (GNU license) and is downloadable from our website in .rpm for LINUX[2]. Versions for other systems are in preparation, and we are happy to hear from others who wish to use AViz and help in its further development.



Bibliography

1
D. Saada, J. Adler and R.Kalish, PRB 59,6650 (1999)

2
http://phycomp.technion.ac.il/$\sim$ aviz