Abstract
Liquids, solution, and liquid crystals present local, but not long-range order. On one hand particles in liquids interacts much strongly than the particles in gas, and this prevents the use of the usual statistical mechanics methods to predict their structure and properties since the needed averaging process must be adapted to this situation. On the other hand, they are not as ordered as the atoms in a crystal and this prohibits the quantum mechanical computing of their electronic properties using symmetry considerations. And since several chemical reactions do not occur in gas phase and biological processes are known to take place only in aqueous environments, the understanding of the microscopic structure and behaviour of liquids is essential.In order to apprehend the importance of intermolecular forces the use of computers has become relatively common and much progress has been made in the field. In the present paper we report the results of computer simulations of different systems and the essay is arranged as follows: in Sec. I, we present a brief description of the advantages of the computer simulation and a definition of the radial distribution function (RDF). Section II explains how water behaves in a liquid phase. Section III will focus on the ionic hydration and on the temperature influence; whereas section IV will look into the non ionic hydration of Argon, tetrafluoromethane and nanopore. Finally, in Sec. V, we draw the main conclusion from our work.
