Molecular ensemble design

Rather, flie assignment is more serious wifli intermolecular interaction potential used. For simple molecules, empirical model potential such as fliose based on Lennard-Jones potential and even hard-sphere potential can be used. But, for complex molecules, potential function and related parameter value should be determined by some theoretical calculations. For example, contribution of hydrogen-bond interaction is highly large to the total interaction for such molecules as HjO, alcohols etc., one can produce semi-empirical potential based on quantum-chemical molecular orbital calculation. Molecular ensemble design is now complex unified mefliod, which contains both quantum chemical and statistical mechanical calculations. 

The scheme to execute these three stages for a large variety of physical properties and substances has been established only to a limited range. Especially, important is the establishment of the third stage, and after that, molecular ensemble design will be worth to discuss. 

Thus, the development of molecular ensemble design is almost completely fumre assignment. In this section, we discuss some attempts to improve prediction at the level of stage (1). It is taken for the convenience s sake from our own effort. This is an example of repeated improvements of prediction method from empirical to molecular level. 

We have already pointed out that statistical mechanical method is indispensable in molecular ensemble design . Full account of molecular simulation is given in some books and will not be reproduced here. Two types of approaches can be classified in applying fliis method. 

We propose a paradigm for physical properties prediction as shown in Figure 2.2.1. This corresponds to the stage (2) and may be used to prepare the process of stage (3), namely, the molecular ensemble design for solvents. 

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