[gmx-users] density_SW_model

[Sang-Min Park]

Dear all,

I ran a 1ns simulation in  SW water (polarizable model) under NPT (P=1 bar , 
T=300 K) conditions.

I checked the density and had a constant plateau value around 640 g/L , which 
is obviously too low. 

I used the flexible and rigid version (520 solvent molecules), with isotropic 
polarizability and used an integrationstep of  0.5 fs  (flexible) 
respectively 1 fs (rigid model).

The other parameters are taken as following : 

emtol               =  0.1
emstep              =  0.002
xtc_precision       =  100000
nstlist             =  10
ns_type             =  grid
rlist               =  1.0
rcoulomb            =  1.0
rvdw                =  1.4
vdwtype =       cut-off
coulombtype         =  PME
fourierspacing      =  0.12
pme_order           =  4
optimize_fft        =  yes

tcoupl              = Berendsen
tc-grps             = Protein      SOL
tau_t               = 0.1  0.1
ref_t               = 300  300
Pcoupl              = Berendsen
tau_p               = 5
compressibility     = 4.5e-5
ref_p               = 1.0

What I have to change in order to reproduce the correct densities (~1Kg/L) as 
reported in JPCB Vol 105 No.13 (2001) ? 

Thank you for your time
Sang Min