[gmx-developers] Reaction field questions (David van der Spoel)

[Noel Carrascal]

David,You asked:>These forces are used to compute the virial and hence the pressure.>Having said that, if you are interested in improved methods for long >range forces, why are you looking at reaction fields?I am interested in isotropic liquids and crystals.  In particular,phase transitions of pure liquids without liquid-solid and liquid-vaporcoexistence(if such think is possible). Under these conditions, reaction field methods give results comparable to Ewald summations at a fraction of the computational cost.
To give you a little bit more context, in case you are curious, I am interested in reproducing and understanding in more depth the problem & debate presented in the followingarticle:http://physicsworld.com/cws/article/news/2013/mar/26/why-water-prefers-the-single-life
Down the road, I would like to apply what I learn to improvements for long range methodsin the simulation of larger biomolecules an other non-isotropic system. Reactions fieldsis just the beginning.
Also, I am running a small test, and the forces given by gromacs differ from my own calculationsfor a simple water system using a simple R script. I assume I am missing something. It is probablythe cut-off scheme that Berk mentioned. 
Thanks for your response
Noel Carrascal 		 	   		  
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