Heating up the system (NVT ensemble : langevin Thermostat)
 &cntrl
  nstlim=50000, dt=0.002,
  ntx=1, irest=0,
  ntf=2, ntc=2,
  ntb=1, ntp=0, ntt=3, gamma_ln=2.0,
  ntpr=1000, ntwr=1000, ntwx=1000,
  tempi=0.0, temp0=300.0,
  cut=8.0,
  nrespa=2,
 &end