[gmx-users] About Anisotropic NPT equilibration to equilibrate the systm.

[Sunil Pokharel]

Dear gromacs users,
I am trying to calculate helmoltz free energy of molecular solid(108
methane molecule) after performing anisotropic NPT equilibration, and
equlibration I do NVT simulation and find Helmoltz free energy. But y
system is not equilibrated , my  equilibration.mdp files looks as
;methane=equilibartion
;PREPROCESSING parameters
integrator          =  md
dt            =.002
nsteps              = 1000000
nstcomm            = 500
;OUPUT CONTROL parameters.
nstxout             =  500
nstvout             =  500
nstfout             =  500
nstlog              =  500
nstenergy           =  500
nstxtcout           =  500
energygrps        =  system
;NEIGHBOUR SEARCHING parameters.
nstlist             =  10
ns_type             =  grid
rlist               =  1.0
;ELECTROSTATIC and VdW parameters.
coulombtype         =  PME
rcoulomb            =  1.0
rvdw                =  1.0
;v-rescale temperature coupling is on in two groups
Tcoupl              =  v-rescale
tc-grps            =  system
tau_t               =  0.01
ref_t               =  150
;PRESSURE COUPLING is on
Pcoupl           = Parrinello-Rahman
Pcoupltype       = anisotropic
; Time constant (ps), compressibility (1/bar) and reference P (bar)
tau-p            = 2
compressibility  = 10.5e-5
ref-p            = 1013
;SIMULATED ANNEALING parameters are not specified.
;GENERATE VELOCITIES is on at 150 K.
gen_vel             =  yes;     ; generate initially
gen_temp            =  150
gen_seed            =  173259    ;give different values for different
trials.
ld_seed            =  1993
;BONDS parameters
constraints         = all-bonds
constraint-algorithm = lincs
lincs-iter         = 4
lincs-order         = 6
pbc                  = xyz

Can anyone help me, for equlibrating  the system?

Thanks !