Dear All, I need to calculate the surface tension of a planar membrane. I believe that the surface tension is calculated something like: gamma = Lz*(Pzz-(Pxx+Pyy)/2). So, if this equation is correct, I have to calculate the pressure tensor and then using the components (average) Pzz,Pxx & Pyy to obtain gamma, right? I was wondering though, is the pressure tensor and hence surface tension calculated over the entire simulation box? Should I divide by two?
Besides, I have been working a little with mbtools package. I ran some simulations for the simplebilayer script, but I get different results with the analytical and tabulated potentials.
Here are some lines of the scripts: ==================================================================================================== set moltypes [list { 0 lipid { 0 1 1 } { 0 1 } } ]
# We use a special type of cosine attractive potential for the tail tail interactions. lappend nb_interactions [list 1 1 lj-cos2 $lj_eps $lj_sigma $ljoffset 1.6 ] =========================================================================================================== I checked my scripts but I couldn't find the mistake. Could you help me with this issue?