Dear Alan, I have not tried that, though I did some MD water simulations with SIESTA that are published. However, I would say that doing MD in that way is not a good way to determine a melting point. The liquid-solid transition is first order, and it will not melt until you greatly overheat the system beyond the melting point of the model. A simulation of 6ps is also not very long.
You probably need to explore thermodynamic integration to estimate the melting point. You might look, for example, at the paper by Stillinger and Weber on silicon, which describes how you might theoretically determine the melting point. My guess is that it will be quite a lot of calculating for SIESTA water, probably impractical to do. Patrick Dr. Patrick Schelling AMPAC Associate Professor Department of Physics University of Central Florida Office: 407-882-1016 email:[email protected] fax: 407-823-5112 >>> "Alan B. de Oliveira" <[email protected]> 03/23/10 7:29 AM >>> Dear all, Have anyone by any chance tested the melting point of a bunch of water molecules with SIESTA? I just tried it using 96 H2O molecules at T = 275K and no melting yet after 6000 MD steps (1fs each step). Thanks in advance, Alan. -- Alan Barros de Oliveira, Professor Universidade Federal de Ouro Preto Instituto de Ciências Exatas e Biológicas Departamento de Física Campus Morro do Cruzeiro Ouro Preto, MG, Brasil. 35400-000. Phone: +55 31 3359 1677 Cell: +55 31 9110 3468
