<P>Add non-translational kinetic energy (heat) to a group of atoms such

that their aggregate momentum is conserved.  Two of these fixes can be

used to establish a temperature gradient across a simulation domain by

adding heat to one group of atoms (hot reservoir) and subracting heat

adding heat to one group of atoms (hot reservoir) and subtracting heat

from another (cold reservoir).  E.g. a simulation sampling from the

McDLT ensemble.  Note that the fix is applied to a group of atoms, not

a geometric region, so that the same set of atoms is affected wherever

<P>Heat addition/subtraction is performed every N timesteps.  The <I>eflux</I>

parameter determines the change in aggregate energy of the entire

group of atoms.  Since eflux is in units of energy/time, this means a

larger value of N will add/subract a larger amount of energy each

larger value of N will add/subtract a larger amount of energy each

timestep the fix is invoked.  If heat is subtracted from the system

too aggressively so that the group's kinetic energy goes to zero,

LAMMPS halts with an error message.

or <A HREF = "fix_temp_rescale.html">fix temp/rescale</A> in that energy is

added/subtracted continually.  Thus if there isn't another mechanism

in place to counterbalance this effect, the entire system will heat or

cool continously.  You can use multiple heat fixes so that the net

cool continuously.  You can use multiple heat fixes so that the net

energy change is 0.0 or use <A HREF = "fix_viscous">fix viscous</A> to drain energy

from the system.

</P>

Add non-translational kinetic energy (heat) to a group of atoms such

that their aggregate momentum is conserved.  Two of these fixes can be

used to establish a temperature gradient across a simulation domain by

adding heat to one group of atoms (hot reservoir) and subracting heat

adding heat to one group of atoms (hot reservoir) and subtracting heat

from another (cold reservoir).  E.g. a simulation sampling from the

McDLT ensemble.  Note that the fix is applied to a group of atoms, not

a geometric region, so that the same set of atoms is affected wherever

Heat addition/subtraction is performed every N timesteps.  The {eflux}

parameter determines the change in aggregate energy of the entire

group of atoms.  Since eflux is in units of energy/time, this means a

larger value of N will add/subract a larger amount of energy each

larger value of N will add/subtract a larger amount of energy each

timestep the fix is invoked.  If heat is subtracted from the system

too aggressively so that the group's kinetic energy goes to zero,

LAMMPS halts with an error message.

or "fix temp/rescale"_fix_temp_rescale.html in that energy is

added/subtracted continually.  Thus if there isn't another mechanism

in place to counterbalance this effect, the entire system will heat or

cool continously.  You can use multiple heat fixes so that the net

cool continuously.  You can use multiple heat fixes so that the net

energy change is 0.0 or use "fix viscous"_fix_viscous to drain energy

from the system.