There are three separate archives containing MOPAC v. 6.0 for OSF/1 in this directory: m60x45.tz (60 heavy atoms, 45 hydrogens) m65x90.tz (65 heavy atoms, 90 hydrogens) m80x100.tz (80 heavy atoms, 100 hydrogens) after copying any of these to your machine do the following: 1) change its name according to UNIX convention, e.g.: mv m60x45.tz m60x45.tar.Z 2) uncompress m60x45.tar 3) in an empty directory untar the archive tar -xf m60x45.tar In the case of any problems with MOPAC for osf1 send me a note: at Mrozek@Trurl.ch.uj.edu.pl Janusz Mrozek, Department of Theoretical Chemistry, Faculty of Chemistry Jagiellonian University Cracow, Poland