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Individual compounds |
Geometries and reference data for a basic set of ~7600 species can be viewed using Jmol or CHIME. A statistical analysis package can be downloaded, this allows sub-sets of the periodic table to be used in an analysis. |
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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 PM6 and X-Ray structures. |
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Strengths and Weaknesses in PM6 |
See Accuracy |
| Hydrogen bonds | The main objective of PM6 is to improve the modeling of hydrogen bonds. The degree to which this has been achieved can be seen in the examples of hydrogen bonds. |
| Polarizability |
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. |