MOLECULAR-DYNAMICS SIMULATIONS OF WATER USING A FLOATING POLYNOMIAL FORCE-FIELD AND AN INTERPOLATING ELECTROSTATIC-FIELD REPRESENTATION

The ability to accurately describe the force field of a molecule is of great importance in spectroscopic and drug design studies. However, the fitting of accurate potential energy functions has proved to be a highly complex task. The description through a simple generic formula of all conformations of a molecule has proved to be a seldom reliable procedure, while more complex representations are increasingly difficult to fit, slower to compute, and difficult to program. In this work, alternative procedures are explored: (1) the intramolecular force fields are expanded in a floating polynomial representation; (2) a fast treatment for the non-bonded interactions is applied. The advantage of these treatments is in their ability to describe highly accurate representations of molecules in a very efficient manner. The main difficulty is a heavy trade off in computer memory usage. Some of the more frequently used force fields for water, and a first principle force field are used as a test of these techniques.