MOPAC®

What MOPAC is

MOPAC (Molecular Orbital PACkage) is a semiempirical quantum chemistry program based on Dewar and Thiel's NDDO approximation.
MOPAC2009 MOPAC2009 is MOPAC2007 plus the MOZYME function.  MOZYME is a linear-scaling SCF method that allows systems of up to 15,000 atoms to be modeled.

MOPAC2007 is an improved version of MOPAC 7.1. In addition to the methods in MOPAC 7.1, it also includes RM1 and PM6. There is increased emphasis on solid-state capabilities. Although the beta test is now finished, help in debugging is always appreciated.  If a bug is detected, please send a message by E-mail, along with an example illustrating the bug. To avoid buggy executables spreading, the executable are normally limited to one year.  Before that date, a new executable will be provided. If you qualify for Academic not-for-profit use and already have a password for MOPAC 2007, go straight to download, otherwise request a password and download.

Commercial users in Japan, please contact Ryoka Systems (see Resellers)
Commercial users in Korea, please contact  KREIS I&C (see Resellers)

References
and Citations
MOPAC2009PM6
Instructions and Manual A new manual is available for MOPAC2009.  Please try finding answers to questions there before sending an E-mail message requesting help.
Maintenance record   MOPAC2009 is under constant maintenance.  If your copy of MOPAC2009 does not work correctly, check the maintenance record to see if there is a more up-to-date version.

PM6

PM6 is the latest parameterization of the NDDO method.  Three modifications to the approximations have been made, these mainly affect the way the core-core interaction is defined.  Parameters have been optimized for most elements, the exceptions being 12 of the lanthanides and all of the actinides.  For details, see the on-line PM6 journal article, and its supplementary material.
Downloads

Downloads of source and  binaries for the various older versions of MOPAC are available.

History MOPAC was started in 1981, and has been under continuous development since then.
MOPAC 7.1 MOPAC 7.1 is a FORTRAN 90 version of MOPAC 7. It supports the methods: MNDO, AM1, and PM3, as well as Sparkle/AM1 for the lanthanides. All published NDDO parameter sets are supported. It is fully in the public domain. (Download source)
Availability Both Windows and Linux versions are supported.
Missing Functions The following functions in MOPAC2002 are not present in MOPAC2007: MINDO/3, PM5, analytical derivatives, the Tomasi solvation model, intersystem crossing.
Cooperative Development The purpose of this site is to encourage cooperative development.  There is a default mechanism for contributing improvements.
Acknowledgment This work was funded by the National Institute of General Medical Sciences (NIGMS), Grant No. 2 R44 GM067327-02
Contacts James Stewart, 15210 Paddington Circle, Colorado Springs, CO 80921
 E-mail : MrMOPAC@OpenMOPAC.net

SKYPE: Jimmy.Stewart2 (between 1500 and 2200 GMT)

The mark "MOPAC" is a trademark of James Stewart
Copyright 2007, Stewart Computational Chemistry.