Talk:Water model
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Models
[edit]One-site models also exist for water. A comprehensive discussion of water models is incomplete without a brief discussion of them. Momolee 11:56, 25 May 2007 (UTC)
- I don't know much about such models, but please feel free to add more information and references. For now, I've deleted the blank 1-site section as it serves no purpose. --Itub 14:29, 4 June 2007 (UTC)
unit problem in equation
[edit]The equation dimensions doesn't make sense,since you are adding C/Å + cal/mol, what unit do you get? Thus constant e should be replaced(?) by Faraday Constant C/mol. Any how I'm working with water now, and I'll be back with more information. GA Fantastic (talk) 10:07, 21 January 2008 (UTC)
- The equation is taken straight from the 1983 reference. However, it is true that it's missing a conversion factor, the electrostatic constant, which depends on the system of units used. Normally the programs implementing water models have it hard-coded (including the e^2 constant) such that (k q_1 q_2)/r gives the energy in kcal/mol when r in in angstrom and q_i in electron charges. --Itub (talk) 12:07, 21 January 2008 (UTC)
- I think this should by clarified on the page, because of possible confusion.Since constans A and B are defined as cal/mol the conversion constant should by set k=332.1. I can't find proper references for the calculations of the constant. More ever I think it would by nice to include table of top (H2O)n cluster, which can by found at http://www-wales.ch.cam.ac.uk/~wales/CCD/TIP4P-water.html as well the geometries of well know clusters. GA Fantastic (talk) 14:17, 21 January 2008 (UTC)
- I checked and I agree that the conversion factor is 332.1. I'll add that to the article. Regarding the clusters, perhaps a more appropriate place is at the water cluster article, but at least I'll add a mention that water models are also used for clusters and not only for bulk liquids! --Itub (talk) 17:43, 21 January 2008 (UTC)
Separate pages for each model.
[edit]It would be great to have one separate page for each water model, where one can find all the properties, produced by that model (e.g., boiling point, freezing point, viscosity, diffusivity, heat conductivity, phase diagram, equilibrium vapor pressure at various temperature, circumstances in which using that model would be good approximation and circumstances in which the model should not be used, etc.) more like characterization of the model).