MOPAC is a general-purpose semi-empirical molecular orbital package for the study of chemical structures and reactions. MOPAC calculates vibrational spectra, thermodynamic quantities, isotopic substitution effects, and force constants for molecules, radicals, ions and polymers. It can carry these out using methods such as AM1, PM3, and PM6.

To run this software interactively in a Linux environment run the commands:

module load mopac
mopac input_file.mop
  mopac input_file.mop 

    where input_file.mop is the MOPAC input file.

    Unfortunately, the version of MOPAC that is available at MSI as a software module prints out a message stating "Your MOPAC executable has expired" and directing the user to upgrade. However, newer versions of MOPAC depend on a version of glibc that is not yet supported on CentOS 6, which the bulk of our lab machines use, and so we are unable to upgrade MOPAC at this time.

    However, while the executable is expired, it still does work normally other than printing out the above message. As a workaround, it is possible to run MOPAC via a wrapper script that skips the message. Create a file with the following contents and a name something like "":

    #!/usr/bin/env sh
    yes "" | mopac "${@}"

    Then set that file to be executable by executing "chmod u+x". This script will then call mopac using the same arguments that you call the script with, and automatically skip past any prompts given by the real mopac executable.


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