Features of PM6 in MOPAC2012 (Home)

 Individual compounds

Geometries and reference data for a basic set of ~7600 species can be viewed using Jmol.

Solid-State Capability

Solids provide a good test for a new method such as PM6.  A preliminary comparison of several predicted structures with X-Ray structures has revealed many errors in PM6.  These are being corrected, slowly.  The current state of PM6 in modeling the geometries of solids can be determined by comparison of PM7, PM6, and  X-Ray structures.

Strengths and Weaknesses in PM6

 See Accuracy


Keywords POLAR and STATIC now generate the polarizability of compounds containing H, C, N, O, F, Si, P, S, Cl, Br, and I, only, with an average unsigned error of 2.1%  (Details)

pKa of -OH groups A new keyword "pKa" has been added.  This will print the pKa of the most acidic hydrogen atom attached to an oxygen.  Average unsigned errors are ~0.41 and RMS errors are 0.54, see pKa results.
Vibrational Frequencies Vibrational frequencies are not well predicted.  The most important fault appears to be that the O-H stretch is much too weak.
Entropy and Heat Capacity PM6 can predict the entropy, S, and heat capacity, Cp, with good accuracy for simple organic species, and slightly lower accuracy for inorganic and more complicated organic species.
Animations A variety of animations of chemical system can be modeled.

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