WMIN program

As the final example of the simplified treatment of an aromatic ring, a novel potential energy calculation of a naphthoquinone derivative (36) with a program called EENY will be briefly mentioned (155). This program seems to resemble WMIN in that it calculates only van der Waals energy. The rotation around the cyclopropyl-quinonoid bonds is calculated to have a barrier of about 10 kcal/mol. In this and another case (156), the results could be considerably improved by full relaxation MM calculations. 

Busing, W. R. 1981. WMIN, a computer program to model molecules and crystals in terms of potential energy functions. Report ORNL-5747. Oak Ridge National Laboratory, Oak Ridge, TN. 

Busing, B. R., WMIN, A Computing Program to Model Molecules and Crystals in Terms of Potential Energy Function, Oak Ridge National Lab Oak Ridge, TN, 1981. 

Ideally, a single A (or B) coefficient would be appropriate for each element type such as one AH for all hydrogens. It has been our experience, however, that atoms of the same element often require different coefficients in different functional groups. There would be, for example, different AH s for H in H-O, H-NR2, H-C(sp2), H-C(sp3), etc. Other complications may involve separate cross terms for each of the atom i - atom j interactions. For a simple molecule such as formaldehyde (H2CO), the Ay cross terms are handled in WMIN with three AH, Ac and Ao coefficients that are used to form the six possible cross terms. But other programs, (e.g. DMAREL) may require cross terms that encompass the Ahh, AHo> AHc, ACc, ACo and Aoo possibilities. This is undoubtedly more flexible and possibly more accurate but does have the disadvantage of requiring the evaluation of many cross term coefficients. Of course, in cases with separate cross terms, one can always use the WMIN simplification of AHo = (AH A0) /2, etc. 

Matsui et al. (1987) used an atomistic simulation approach to study the ilmenite and perovskite phases of MgSiOj and employed the wmin computer program (Busing, 1981) to produce a potential model based on em-... 

In an analysis in 1973 of the effect of packing on the conformation of triphenylphosphine, Brock and Ibers used the 1972 version of Busing s program WMIN. ° The calculations extended beyond the minimization of close contacts between rigid molecules, taking into account internal molecular strain, and van der Waals and Coulomb interactions. 

Busing WR (1981) WMIN, A Computer Program to Model Molecirles and Crystals in Terms of Potential Energy Functions ORNL-5747 Oak Ridge National Laboratory Oak Ridge Catlow CRA, Bell RG, and Gale JD (1994) Computer modelling as a technique in materials chemistry. J Mater Chem 4 781-792... 

NOTE GDP = gross domestic product, Wmin = minimum wage, Wmk = market wage, Wpr = program wage. 

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