Structurally bound water, description

For a cytosine stack model calculations have been performed to investigate the effect of water molecules on its electronic structure (16). In this first approach the water structure of a cytidine unit in aperiodic B-DNA obtained with the help of Monte Carlo computer experiments (17) has been used. This choice of the water structure, of course, does not give a realistic description for cytosine,but we get in a relatively simple model calculation an order of magnitude estimate of the effects. The bound water molecules act on the electronic system of the stacked nucleotide bases as an external field. By a proper representation of the electron distribution of the water molecules through point charges one can easily calculate the matrix elements of this perturbing field in terms of the Bloch functions of the finite polymer and include in this way its effect on the band structure. 

The effect of free surface liquor content in a bulk material, as opposed to bound moisture or water of composition, is to alter the physical and geometric structure of the mass. Water is a common component of liquor/solids mixtures and can be present in a wide range of proportions, categorized by descriptions that reflect increasing moisture content as ... 

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