We present an extensive integral equation study of a simple point charge model of water for a variety of thermodynamic states ranging from the vapor phase to the undercooled liquid. The calculations are carried out in the molecular reference-hypernetted chain approximation and the results are compared with extensive molecular dynamics simulations. Use of a hard sphere fluid as a reference system to provide the input reference bridge function leads to relatively good thermodynamics. However, at low temperatures the computed microscopic structure shows deficiencies that probably stem from the lack of orientational dependence in this bridge function. This is in marked contrast with results previously obtained for systems that, although similarly composed of angular triatomic molecules, do not tend to the tetrahedral coordinations that are characteristic of water.

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In this work we describe a detailed study of the conformational properties of flexible polymer chains confined into rigid wall spherical cavities of different sizes, with dimensions comparable to those of the chains. An off-lattice Monte Carlo algorithm has been used to simulate the behavior of excluded-volume, freely jointed chains in a wide range of concentrations. The considered properties include the size and shape of the chains, different densities of the system, and the orientation of certain characteristic vectors. All these properties are analyzed as a function of the position in the spherical cavity, trying to determine how each property is affected by the presence of the spherical rigid wall. A comparison with the results found in the literature for polymer systems confined between infinite parallel plates is done whenever possible, with some significant differences.