MOPAC version 23.2.4

This is a very minor patch release that only updates the citation guidelines in the MOPAC output, citation, and readme files. The preferred citation for MOPAC use in scientific publications is now the recent Journal of Open Source Software (JOSS) paper [https://doi.org/10.21105/joss.08025].

MOPAC version 23.2.3

This patch release is synchronized with the acceptance of an open-source MOPAC release paper in the Journal of Open-Source Software (JOSS). It contains a few very minor bug fixes, and the main MOPAC distribution is now packaged with a set of basic examples of MOPAC calculations on the command line and through the recently released API. Another patch release will soon follow the publication of the JOSS paper with updated citation information, once the paper is available to be cited.

MOPAC version 23.2.2

This patch contains more API bug fixes and better support for interoperability between restricted and unrestricted Hartree-Fock (RHF & UHF) calculations. Specifically, the mopac_state output can be used as an input between RHF and UHF calculations. A UHF input will force an RHF calculation into a UHF calculation, and an RHF input will initialize a UHF calculation to a spin-symmetric density matrix. The RHF vs. UHF choice is determined automatically by the API, and this process previously had a bug when alternating between RHF and UHF calculations.

What's Changed

• Better API UHF support by @godotalgorithm in #300
• Update patch version by @godotalgorithm in #301

Full Changelog: v23.2.1...v23.2.2

MOPAC version 23.2.1

Some bug fixes, the main priority being prompt correction of any API bugs as they are discovered. This patch release fixes API bugs associated with failures for odd charges and PM6-D3H4 and incorrect dipole moments when some atoms are frozen.

What's Changed

• Distinguish between PRECISE and PRECISION keywords by @godotalgorithm in #290
• Time limit for MOZYME 1SCF by @godotalgorithm in #294
• Change jsmol path to relative base URL by @godotalgorithm in #297
• Fix API bugs by @godotalgorithm in #298
• Update patch version by @godotalgorithm in #299

Full Changelog: v23.2...v23.2.1

MOPAC version 23.2

This version is mainly a collection of bug fixes and minor feature enhancements. It is a minor version release because some of MOPAC's semiempirical models have been changed in a way that has a large effect in a rare, narrow set of circumstances.

A carbon-carbon triple bond correction added to all PM6-based models and PM7 was creating a discontinuity and erroneous minimum in the potential energy surface between the C-C double and triple bond lengths. The correction has been adjusted in this intermediate bonding regime, but there is no change when C-C distances are shorter than 1.21 A or longer than 1.33 A.

The iodine parameters have been changed in the PM6-ORG model to avoid unphysical sulfur-iodine bonding configurations. All PM6-ORG calculations with iodine atoms will have small numerical differences in their results.

What's Changed

• Fixes a minor printing bug for H bonds with labeled atoms by @godotalgorithm in #259
• Fixes another minor printing bug for H bonds with labeled atoms by @godotalgorithm in #260
• COSMO memory reduction by @godotalgorithm in #270
• Update linux GHA runner versions (test) by @godotalgorithm in #271
• Remove zero-electron barrier for gradients by @godotalgorithm in #274
• Update Windows runner version by @godotalgorithm in #275
• Fix iodine parameters in PM6-ORG model by @godotalgorithm in #277
• Add QMMM support to MOZYME by @godotalgorithm in #280
• Triple bond fix by @godotalgorithm in #281
• UHF Mulliken charges by @godotalgorithm in #283
• Time limit for SCF cycle by @godotalgorithm in #284
• Remove last defunct references to Java & JMol by @godotalgorithm in #286
• API crash fix for SCF calculations by @godotalgorithm in #287
• Minor version bump to 23.2 by @godotalgorithm in #288

Full Changelog: v23.1.2...v23.2

MOPAC version 23.1.2

This patch fixes another small API bug that was detected while testing mopactools. SCF calculations were failing if there were no moveable atoms or lattice vectors.

MOPAC version 23.1.1

This patch fixes 2 bugs in the MOPAC API - the version number returned by the API call was erratic, and the bond-order matrix had an indexing problem unless it was calculated using the Fortran wrapper.

MOPAC version 23.1.0

This is the first open-source MOPAC release under an Apache license. The switch from an LGPL license is to encourage and facilitate more contributions from industry. This release also adds a version command to the recent API that will be used by MOPAC's upcoming Python wrapper library, mopactools.

Less visible are various bug fixes and portability enhancements. The standalone distribution is still not built with MDI support enabled, but the conda-forge distribution of this MOPAC version will have MDI support enabled and depend on the MDI library available through conda-forge. Several build options have been added (USE_C_MALLOC, FORCE_EXPORT_SYMBOLS) that allow MOPAC to be built using recent versions of the LLVM Flang compiler, which will hopefully enable MOPAC to complete its migration to LLVM Flang on conda-forge.

What's Changed

• Fix a few zero valence electron bugs by @godotalgorithm in #236
• Fix dielectric energy of zero for systems without valence electrons by @godotalgorithm in #237
• Ignore single-character labels when printing H bonds by @godotalgorithm in #238
• Change license from LGPL to Apache by @godotalgorithm in #243
• API cleanup by @godotalgorithm in #246
• Initialize the convergence flag in LOCATE-TS by @godotalgorithm in #247
• Print thread count for all calculations if OpenMP is available by @godotalgorithm in #248
• Fix LOCATE-TS convergence criterion by @godotalgorithm in #249
• MDI enhancements by @godotalgorithm in #250
• Remove unnecessary options from open commands by @godotalgorithm in #251
• Enhance MDI portability by @godotalgorithm in #252
• Add CMake option for using C malloc/free in API by @godotalgorithm in #253
• Bump to version 23.1 by @godotalgorithm in #254

Full Changelog: v23.0.3...v23.1.0

MOPAC version 23.0.3

This is another rapid-response patch for a bug in the new API. The latest bug caused diskless API calls to fail silently for molecules with exactly 4 atoms.

MOPAC version 23.0.2

This is a patch to remove a stray file that was being erroneously generated by calls to the diskless API, thus interfering with its strict "diskless" status.