Local Structure and Work of Formation of Water Clusters Studied by Molecular Dynamics Simulations

✍ Scribed by Elena N. Brodskaya; Jan Christer Eriksson; Aatto Laaksonen; Anatoly I. Rusanov

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 240 KB
• Volume: 180
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1996.0276

✦ Synopsis

Here d is the distance between the equimolecular dividing Small clusters composed of 64, 94, 125, 190, 256, and 512 water surface with the radius R e and the surface of tension with molecules have been studied by molecular dynamics simulations radius R s , i.e., d Å R e 0 R s and, to be precise, R stands using the ST2 water model. Radial profiles of the local density, either for R e or R s . By assuming d to be a constant and energy, electric potential, and components of the pressure tensor integrating Eq. [1], Tolman (loc.cit.) obtained the depenwere calculated. The work of formation was derived for the differdence of g on R in the limit of large R ent cluster sizes on the basis of the normal pressure tensor component P N and was related to the curvature-dependent surface tension of the clusters. Our calculations show that the surface tension

g increases with the cluster radius R in the size range investigated, to beyond the limiting value for the flat interface. This course of where g ϱ and d ϱ relate to the planar interface. This expresthe g(R) function is consistent with the corresponding surface sion should thus hold true for large enough values of R. A energy function which was obtained in a more direct manner from crude estimate of d ϱ for a simple fluid yields that it is likely the energetic parameters. In addition, it indicates, however, that to be a positive quantity and of a magnitude corresponding the ST2 water model yields surface entropy values which are much to a fraction of a molecular diameter (3). The main crux lower than anticipated for real water. We have also elucidated the related with the above equations is, however, that one cannot surface effect on the self-diffusion coefficient and on the reorientaeasily judge where R is large enough to justify putting d(R) tional relaxation time.