[gmx-users] high initial temperature with low ref_T

[Dongsheng Zhang]

Hello, GMX users,

My system exploded very soon after mdrun. So I outputted the log file
every step. I found the initial temperature is about 800 K even though I
set ref_T = 300. Why does this happen?


The following is from my mdp file:

tau_t                    = 0.1   0.1
ref_t                    = 300   300
gen_vel                  = yes
gen_temp                 = 300

The following is from my log file:

Group rest with mass  1.71792e+04, Ekrot  2.03838e+00 Det(I) =  2.78698e
+12
  COM:     -0.44251      -0.27562       3.39794
  P:       -0.14897      -0.02236       0.01592
  V:       -0.00001      -0.00000       0.00000
  J:      444.35214    -180.86247     -18.52021
  w:        0.00820      -0.00216      -0.00236
Inertia tensor (3x3):
   Inertia tensor[    0]={ 1.29701e+04,  5.56416e+03, -4.20521e+03}
   Inertia tensor[    1]={ 5.56416e+03,  7.12549e+03, -2.55740e+03}
   Inertia tensor[    2]={-4.20521e+03, -2.55740e+03,  4.68307e+04}
   Energies (kJ/mol)
           Bond          Angle       G96Angle Ryckaert-Bell.
LJ-14
    2.23601e+03    3.10376e+02    9.73565e+02    4.90946e+03    3.92667e
+04
     Coulomb-14        LJ (SR)   Coulomb (SR)      Potential    Kinetic
En.
    3.73370e+03   -3.85288e+03   -3.22634e+03    4.43506e+04    1.88193e
+04
   Total Energy    Temperature Pressure (bar)
    6.31699e+04    8.38307e+02    0.00000e+00

           Step           Time         Lambda
              1        0.00200        0.00000


thank you for your help!


Dongsheng