Visualizing the results of molecular orbital calculations
 1) MO program:  gaussian, gamess, mopac, etc.
 2) display molecule in 3D:  geo-opt, single-point, nomal mode (animation)
 3) density:  contour plot or 3D view for electron density and MO coefficient
Everything what you want about MO calculation can be seen.

WWW: http://www.caos.kun.nl/~schaft/molden/molden.html

You must set the environmental variable ether ORIGINALBINARY=yes or 
MYBINARY=yes. The latter will be used for building up your own binary, 
which is specially customized.
web site, shown above.

Acknowledgement:  Porting to 4.0-CURRENT (__FreeBSD_version == 400005) 
and later versions have been assisted greatly by Glenn Johnson 
<gjohnson@nola.srrc.usda.gov>, thanks a lot !

--
rmiya