What MOPAC is
|MOPAC (Molecular Orbital PACkage) is a semiempirical quantum chemistry
program based on Dewar and Thiel's NDDO approximation. Most users use
MOPAC with a Graphical User
MOPAC2012 with improved handling of biomolecules. If a bug is detected, please
send a message by E-mail to MrMOPAC@OpenMOPAC.net, along with an example
illustrating the bug. If you qualify for Academic not-for-profit use and already have a password
for MOPAC 2012, go straight to
request a password and
For commercial and governmental prices, see
Instructions for use with Chem3D.
|PM7||PM7 is a modified form of PM6. A few errors
in NDDO theory that affect large systems have been removed. All atomic
and diatomic parameters were re-optimized. Average errors in organic
compounds have been reduced by ~10%, and errors in large organics and
have been significantly reduced, see
|Reducing Computation Time||Computation time has been reduced, in some cases by over
99%, as a result of using the Intel Math Kernel Library (MKL) and by
parallelizing parts of the code. For details, see
|GPU||Recently, MOPAC2016 was modified to allow NVIDIA GPU acceleration to be used, for details, see GPU, this allows large systems that do not use MOZYME to run between two to just over three times faster than with just MKL and parallelization. MOZYME jobs do not run faster when a GPU chip is used. Read Requirements for GPU MOPAC before installing it.|
|MOPAC2016 MOPAC2009, PM6, PM7|
|Instructions and Manual||A manual
is available for MOPAC2016. Please try finding answers to questions there
before sending an E-mail message requesting help. For individual topics of
interest, see Discussion Topics.
|Maintenance record||MOPAC2016 is under constant
maintenance. If your copy of MOPAC2016
does not work correctly, check the maintenance record to see if there is a
more up-to-date version.
|PM6 is a re-parameterization of the NDDO method. Three modifications to the approximations
these mainly affect the way the core-core interaction was defined.
Parameters were optimized for most elements, the exceptions being 12 of the
lanthanides and all of the actinides. The lanthanides can be
represented by sparkles. For details, see the on-line
PM6 journal article, and its
Downloads of source and binaries for the various
older versions of MOPAC are
available, as well as utility programs such as BZ and MAKPOL.
|History||MOPAC was started in 1981, and has been under
continuous development since then.
|Older MOPAC Programs||MOPAC2012 is
MOPAC2009 plus PM7 and PM7-TS.
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 was an improved version of MOPAC 7.1. In addition to the methods in MOPAC 7.1, it also included RM1 and PM6.
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 were supported. It is fully in the public domain. (Download source)
|Availability||32 and 64 bit Windows, 32 bit and 64 bit Linux,
CentOS-5, CentOS-6, CentOS-7, and
64 bit Mac versions are
|Cooperative Development||The purpose of this site is to encourage
cooperative development. There is a
default mechanism for contributing
|Acknowledgment||This work was funded by the National
Institute of General Medical Sciences (NIGMS), Grant No. 2 4R44GM108085-02|
|Contacts||James Stewart, 15210 Paddington Circle,
Colorado Springs, CO 80921|
E-mail : MrMOPAC@OpenMOPAC.net
SKYPE: Jimmy.Stewart2 (between 1500 and 2200 GMT)