Page 270 - Handbook Of Multiphase Flow Assurance

Molecular modeling 269

FIG. 10.39 RDF oxygen-oxygen for SPC model and water at 220 K (298 K scaled) with scaled dielectric function.
♦♦♦, Narten and Lewy (1971), _ _ _, this work).

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water model to simulate liquid water at a temperature of 283 K and a density of 1.0 g/cm .
They used the adaptation of the program written by Dr. Lester Guttman to enumerate the
distribution of hydrogen bond polygons. The results for water structure from their simulation
are shown in Fig. 10.40.
In order to process the results of SYBYL® simulations, a program for determining the hy-
drogen bond patterns in water was independently written in Pascal. This program allows to
determine the number distribution of H-bonded water molecules arranged in polygon ring-
like structures. This program is very computationally intensive due to the multi-branch loop
algorithm of search and validation of hydrogen bonded polygons. The code is presented in
the Computer Code section. The search part consists of exhaustive search of the honeycomb-
like hydrogen bonded patterns. When the pattern closes or comes to the starting point in
a certain number of steps (between 3 and 15), a 3- to 15-sided polygon is said to be found.