git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@4652 f3b2605a-c512-4ea7-a41b-209d697bcdaa

This commit is contained in:
sjplimp 2010-09-01 20:17:25 +00:00
parent d6a892f246
commit ed40d27145
6 changed files with 41 additions and 31 deletions

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@ -135,6 +135,7 @@ commands)
charged pairwise potentials: Coulombic, point-dipole
manybody potentials: EAM, Finnis/Sinclair EAM, modified EAM (MEAM), \
embedded ion method (EIM), Stillinger-Weber, Tersoff, AI-REBO, ReaxFF, COMB
electron force field (eFF)
coarse-grained potentials: DPD, GayBerne, REsquared, colloidal, DLVO
mesoscopic potentials: granular, Peridynamics
bond potentials: harmonic, FENE, Morse, nonlinear, class 2, \

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@ -22,16 +22,17 @@ compute myTemp all temp/deform/eff :pre
[Description:]
Define a computation that calculates the temperature of a group of
nuclei and electrons using the electron force field, after subtracting
out a streaming velocity induced by the simulation box changing size
and/or shape, for example in a non-equilibrium MD (NEMD) simulation.
The size/shape change is induced by use of the "fix
deform/eff"_fix_deform_eff.html command. A compute of this style is
created by the "fix nvt/sllod/eff"_fix_nvt_sllod_eff.html command to
compute the thermal temperature of atoms for thermostatting purposes.
A compute of this style can also be used by any command that computes
a temperature, e.g. "thermo_modify"_thermo_modify.html, "fix
npt/eff"_fix_nh.html, etc.
nuclei and electrons in the "electron force field"_pair_eff.html
model, after subtracting out a streaming velocity induced by the
simulation box changing size and/or shape, for example in a
non-equilibrium MD (NEMD) simulation. The size/shape change is
induced by use of the "fix deform/eff"_fix_deform_eff.html command. A
compute of this style is created by the "fix
nvt/sllod/eff"_fix_nvt_sllod_eff.html command to compute the thermal
temperature of atoms for thermostatting purposes. A compute of this
style can also be used by any command that computes a temperature,
e.g. "thermo_modify"_thermo_modify.html, "fix npt/eff"_fix_nh.html,
etc.
The calculation performed by this compute is exactly like that
described by the "compute temp/deform"_compute_temp_deform.html

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@ -23,9 +23,10 @@ compute mine flow temp/region/eff boundary :pre
[Description:]
Define a computation that calculates the temperature of a group of
nuclei and electrons wihtin a geometric region using the electron
force field. A compute of this style can be used by commands that
compute a temperature, e.g. "thermo_modify"_thermo_modify.html.
nuclei and electrons in the "electron force field"_pair_eff.html
model, within a geometric region using the electron force field. A
compute of this style can be used by commands that compute a
temperature, e.g. "thermo_modify"_thermo_modify.html.
The operation of this compute is exactly like that described by the
"compute temp/region"_compute_temp_region.html command, where the

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@ -60,7 +60,10 @@ interactions (<A HREF = "pair_style.html">pair_style</A>).
<P>The Ff and Fr terms are added by this fix on a per-particle basis.
</P>
<P>Ff is a frictional drag or viscous damping term proportional to the
particle's velocity (including the electronic radial degrees of freedom). The proportionality constant for each atom is computed as m/damp, where m is the mass of the particle and damp is the damping factor specified by the user.
particle's velocity (including the electronic radial degrees of
freedom). The proportionality constant for each atom is computed as
m/damp, where m is the mass of the particle and damp is the damping
factor specified by the user.
</P>
<P>Fr is a force due to solvent atoms at a temperature T randomly bumping
into the particle. As derived from the fluctuation/dissipation
@ -73,15 +76,18 @@ the direction and magnitude of this force as described in
a Gaussian random number) for speed.
</P>
<P>Note that the thermostat effect of this fix is applied to the
translational and electronic radial degrees of freedom for the particles in a system. The translational degrees of freedom can also have a bias
velocity removed from them before thermostatting takes place; see the
description below.
translational and electronic radial degrees of freedom for the
particles in a system. The translational degrees of freedom can also
have a bias velocity removed from them before thermostatting takes
place; see the description below.
</P>
<P>IMPORTANT NOTE: Unlike the <A HREF = "fix_nh_eff.html">fix nvt/eff</A> command which
performs Nose/Hoover thermostatting AND time integration, this fix
does NOT perform time integration. It only modifies forces to effect
thermostatting. Thus you must use a separate time integration fix,
like <A HREF = "fix_nve_eff.html">fix nve/eff</A> to actually update the velocities (including electronic radial velocities) and positions of atoms (nuclei and electrons) using the modified forces. Likewise, this fix
like <A HREF = "fix_nve_eff.html">fix nve/eff</A> to actually update the velocities
(including electronic radial velocities) and positions of atoms
(nuclei and electrons) using the modified forces. Likewise, this fix
should not normally be used on atoms that also have their temperature
controlled by another fix - e.g. by <A HREF = "fix_nh.html">fix nvt/eff</A> command.
</P>
@ -106,13 +112,14 @@ the remaining thermal degrees of freedom, and the bias is added back
in.
</P>
<P>The <I>damp</I> parameter is specified in time units and determines how
rapidly the temperature is relaxed. For example, a value of 0.1
means to relax the temperature in a timespan of 100 timesteps (for the default 0.001 timesteps and fmsec unit used in eFF - see the <A HREF = "units.html">units</A> command).
The damp factor can be thought of as inversely related to the
viscosity of the solvent. I.e. a small relaxation time implies a
hi-viscosity solvent and vice versa. See the discussion about gamma
and viscosity in the documentation for the <A HREF = "fix_viscous.html">fix
viscous</A> command for more details.
rapidly the temperature is relaxed. For example, a value of 0.1 means
to relax the temperature in a timespan of 100 timesteps (for the
default 0.001 timesteps and fmsec unit used in eFF - see the
<A HREF = "units.html">units</A> command). The damp factor can be thought of as
inversely related to the viscosity of the solvent. I.e. a small
relaxation time implies a hi-viscosity solvent and vice versa. See
the discussion about gamma and viscosity in the documentation for the
<A HREF = "fix_viscous.html">fix viscous</A> command for more details.
</P>
<P>The random # <I>seed</I> must be a positive integer. A Marsaglia random
number generator is used. Each processor uses the input seed to
@ -182,7 +189,7 @@ LAMMPS</A> section for more info.
</P>
<P><B>Related commands:</B>
</P>
<P><A HREF = "fix_nh.html">fix nvt/eff</A>
<P><A HREF = "fix_langevin.html">fix langevin</A>
</P>
<P><B>Default:</B>
</P>

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@ -15,10 +15,10 @@
</P>
<P>pair_style eff/cut cutoff eradius_limit_flag pressure_flag
</P>
<P>cutoff = global cutoff for Coulombic interactions
eradius_limit_flag = 0 or 1 for whether electron size is restrained (optional)
pressure_flag = 0 or 1 to define the type of pressure calculation (optional)
</P>
<UL><LI>cutoff = global cutoff for Coulombic interactions
<LI>eradius_limit_flag = 0 or 1 for whether electron size is restrained (optional)
<LI>pressure_flag = 0 or 1 to define the type of pressure calculation (optional)
</UL>
<P><B>Examples:</B>
</P>
<PRE>pair_style eff/cut 39.7

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@ -14,7 +14,7 @@ pair_style eff/cut cutoff eradius_limit_flag pressure_flag
cutoff = global cutoff for Coulombic interactions
eradius_limit_flag = 0 or 1 for whether electron size is restrained (optional)
pressure_flag = 0 or 1 to define the type of pressure calculation (optional)
pressure_flag = 0 or 1 to define the type of pressure calculation (optional) :ul
[Examples:]