Comment here: this is an implicit-solvent MD run.
&cntrl
  ntx    = 1,       !Read coordinates but no velocities
  irest  = 0,       !This is not a restart 
  ntb    = 0,       !No periodic box
  igb    = 8,       !Use a continuum solvent model
  gbsa   = 1,       !Apply a surface energy
  cut    = 20,      !Cut off interactions after 20A
  ntr    = 0,       !No restrained atoms  
  ntc    = 2,       !Hold covalent bonds with H atoms rigid
  ntf    = 2,       !Do not calculate H atom bond stretching
  ntt    = 3,       !Use a Langevin thermostat  
  temp0  = 300.0,   !Langevin bath temperature is 300K
  gamma_ln = 0.01,  !Coupling to bath 
  ig     = -1,      !Seed
  nstlim = 100000,  !Number of MD steps
  dt = 0.002,       !Length of step (fs)
  nscm = 10000,     !Centre the system every nscm steps.
  ntpr = 500, ntwx = 500, ntwr = 1000 !output frequencies
/