[gmx-users] System reaches ~124K after simulated annealing upto 300K

[Apramita Chand]

Dear All,
I have used the following nvt.mdp file to gradually warm my system upto
300K but just reach upto 124K. I have used variety of options in the
simulated annealing like taking less no. of time intervals but in vain
Then, I have to perform manually the gradual heating process which takes me
to 300K
Why doesn't this work?

Yours sincerely,
Apramita



 VARIOUS PREPROCESSING OPTIONS
define                   = -DPOSRES
; RUN CONTROL PARAMETERS
integrator               = md
dt                       = 0.002 ; time step (in ps)
nsteps                   = 50000 ; number of steps
; OUTPUT CONTROL OPTIONS
nstxout                 = 500   ; save coordinates every ps
nstvout                 = 500   ; save velocities every ps
nstenergy               = 500   ; save energies every ps
nstlog                  = 500   ; update log file every ps
energygrps              = Protein SOL
; NEIGHBORSEARCHING PARAMETERS
nstlist                  = 5
ns_type                  = grid
pbc                      = xyz
rlist                    = 0.9
; OPTIONS FOR ELECTROSTATICS AND VDW
coulombtype              = PME  ; Particle Mesh Ewald for long-range
electrostatics
pme_order                = 4    ; cubic interpolation
fourierspacing           = 0.16 ; grid spacing for FFT
rcoulomb                 = 0.9
vdw-type                 = Cut-off
rvdw                     = 1.4
; Temperature coupling
5
tcoupl                   = v-rescale            ; Couple temperature to
external heat bath according to velocity re-scale method
tc-grps                  =  Protein  SOL ; Use separate heat baths for
Protein and Non-Protein groups
tau_t                    = 0.1        0.1        ; Coupling time constant,
controlling strength of coupling
ref_t                    = 300        300    ; Temperature of heat bath
; Dispersion correction
DispCorr                 = EnerPres ; account for vdw cut-off
; Pressure coupling is off
pcoupl                  = no                    ; no pressure coupling in
NVT
; GENERATE VELOCITIES FOR STARTUP RUN
gen_vel                  = yes    ; Assign velocities to particles by
taking
them randomly from a Maxwell distribution
Different numbers give different sets of velocities
gen_temp                 = 300    ; Temperature to generate corresponding
Maxwell distribution
gen_seed                 = -1     ; Seed for (semi) random number
generation.
; OPTIONS FOR BONDS
constraints              = all-bonds ; All bonds will be treated as
constraints (fixed length)
continuation             = no           ; first dynamics run
constraint_algorithm     = lincs        ; holonomic constraints
lincs_iter               = 1            ; accuracy of LINCS
lincs_order              = 4            ; also related to accuracy
; Simulated Annealing
annealing= single single
annealing_npoints= 4 4
annealing_time= 0 50 75 100 0 50 75 100
annealing_temp= 0 100 200 300 0 100 200 300