I did an NVT simulation of 10000 timesteps (default
timestep of 1 fs) with these settings:
fix 1 all nvt 300.0 300.0 100
I naively set thermo_style to output "step temp press
etotal" and got this output:
Step Temp Press TotEng
152 0 46402.944 -207716.19
153 5.3252455e-06 46402.944 -207716.19
154 2.1261871e-05 46402.944 -207716.19
155 4.769303e-05 46402.943 -207716.19
156 8.4425601e-05 46402.943 -207716.19
157 0.00013119259 46402.943 -207716.19
158 0.00018765647 46402.943 -207716.19
159 0.00025341333 46402.943 -207716.19
160 0.00032799795 46402.943 -207716.19
161 0.00041088947 46402.943 -207716.19
162 0.00050151783 46402.943 -207716.19
163 0.00059927078 46402.943 -207716.19
...
The temperature appears absurdly low, but that seems
to have something to do with this in the docs for "fix
nvt":
"This fix computes a temperature each timestep. To do
this, the fix creates its own compute of style "temp",
as if this command had been issued:
compute fix-ID_temp group-ID temp
"See the compute temp command for details. Note that
the ID of the new compute is the fix-ID with
underscore + 'temp' appended and the group for the new
compute is the same as the fix group.
"Note that this is NOT the compute used by
thermodynamic output (see the thermo_style command)
with ID = thermo_temp. This means you can change the
attributes of this fix's temperature (e.g. its
degrees-of-freedom) via the compute_modify command or
print this temperature during thermodyanmic output via
the thermo_style custom command using the appropriate
compute-ID. It also means that changing attributes of
thermo_temp will have no effect on this fix.
Alternatively, you can directly assign a new compute
(for calculating temeperature) that you have defined
to this fix via the fix_modify command."
I'm not sure *quite* what's going on, though, and I'm
especially not sure if I've done anything wrong
besides using "temp" instead of "1_temp" (?).