Energy minimisation method

Following the recently developed energy minimisation method described by M.U. Schmidt [2], for the first time three dimensional crystal structure determinations were carried out with P.Y.13 and P.Y.14 [3]. The studies showed the molecules to be planar with the terminal phenyl rings twisted by 4-10° with respect to the acetoacetyl fragments, the degree of planarity of P.Y.14 found to be a little lower than that of P.Y.13. 

Determine thermodynamic relationships between these species by using the free energy minimisation method, i.e., the fact that the free energy is minimum at equilibrium. 

A combined Monte Carlo and energy minimisation method has been developed to model zeolitic materials with low and medium Si/Al and with a variety of extra-framework species. We present results for Na- and H-Mordenites with Si/Al of 5 and 11. The A1 and cation distributions obtained are in reasonably good agreement with experimental studies. Furthermore, our calculated vibrational spectra are in excellent agreement with experiment, which has allowed us to re-interpret the de-convolution and assignment of the various acid sites. 

The program builds models rapidly, and construction time increases linearly with the structural complexity of the target. This is in contrast to energy minimisation methods which increase exponentially with the number of atoms in the target. 

Sutton AP (1992) Direct free energy minimisation methods apphcation to grain boimdaries. Phil Trans Roy Soc London A 341 233-245... 

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