Page Menu
Home
c4science
Search
Configure Global Search
Log In
Files
F93755184
pair_class2.txt
No One
Temporary
Actions
Download File
Edit File
Delete File
View Transforms
Subscribe
Mute Notifications
Award Token
Subscribers
None
File Metadata
Details
File Info
Storage
Attached
Created
Sun, Dec 1, 05:47
Size
6 KB
Mime Type
text/x-c++
Expires
Tue, Dec 3, 05:47 (2 d)
Engine
blob
Format
Raw Data
Handle
22693641
Attached To
rLAMMPS lammps
pair_class2.txt
View Options
"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)
:line
pair_style lj/class2 command :h3
pair_style lj/class2/cuda command :h3
pair_style lj/class2/gpu command :h3
pair_style lj/class2/kk command :h3
pair_style lj/class2/omp command :h3
pair_style lj/class2/coul/cut command :h3
pair_style lj/class2/coul/cut/cuda command :h3
pair_style lj/class2/coul/cut/kk command :h3
pair_style lj/class2/coul/cut/omp command :h3
pair_style lj/class2/coul/long command :h3
pair_style lj/class2/coul/long/cuda command :h3
pair_style lj/class2/coul/long/gpu command :h3
pair_style lj/class2/coul/long/kk command :h3
pair_style lj/class2/coul/long/omp command :h3
[Syntax:]
pair_style style args :pre
style = {lj/class2} or {lj/class2/coul/cut} or {lj/class2/coul/long}
args = list of arguments for a particular style :ul
{lj/class2} args = cutoff
cutoff = global cutoff for class 2 interactions (distance units)
{lj/class2/coul/cut} args = cutoff (cutoff2)
cutoff = global cutoff for class 2 (and Coulombic if only 1 arg) (distance units)
cutoff2 = global cutoff for Coulombic (optional) (distance units)
{lj/class2/coul/long} args = cutoff (cutoff2)
cutoff = global cutoff for class 2 (and Coulombic if only 1 arg) (distance units)
cutoff2 = global cutoff for Coulombic (optional) (distance units) :pre
[Examples:]
pair_style lj/class2 10.0
pair_coeff * * 100.0 2.5
pair_coeff 1 2* 100.0 2.5 9.0 :pre
pair_style lj/class2/coul/cut 10.0
pair_style lj/class2/coul/cut 10.0 8.0
pair_coeff * * 100.0 3.0
pair_coeff 1 1 100.0 3.5 9.0
pair_coeff 1 1 100.0 3.5 9.0 9.0 :pre
pair_style lj/class2/coul/long 10.0
pair_style lj/class2/coul/long 10.0 8.0
pair_coeff * * 100.0 3.0
pair_coeff 1 1 100.0 3.5 9.0 :pre
[Description:]
The {lj/class2} styles compute a 6/9 Lennard-Jones potential given by
:c,image(Eqs/pair_class2.jpg)
Rc is the cutoff.
The {lj/class2/coul/cut} and {lj/class2/coul/long} styles add a
Coulombic term as described for the "lj/cut"_pair_lj.html pair styles.
See "(Sun)"_#Sun for a description of the COMPASS class2 force field.
The following coefficients must be defined for each pair of atoms
types via the "pair_coeff"_pair_coeff.html command as in the examples
above, or in the data file or restart files read by the
"read_data"_read_data.html or "read_restart"_read_restart.html
commands, or by mixing as described below:
epsilon (energy units)
sigma (distance units)
cutoff1 (distance units)
cutoff2 (distance units) :ul
The latter 2 coefficients are optional. If not specified, the global
class 2 and Coulombic cutoffs are used. If only one cutoff is
specified, it is used as the cutoff for both class 2 and Coulombic
interactions for this type pair. If both coefficients are specified,
they are used as the class 2 and Coulombic cutoffs for this type pair.
You cannot specify 2 cutoffs for style {lj/class2}, since it has no
Coulombic terms.
For {lj/class2/coul/long} only the class 2 cutoff can be specified
since a Coulombic cutoff cannot be specified for an individual I,J
type pair. All type pairs use the same global Coulombic cutoff
specified in the pair_style command.
:line
If the pair_coeff command is not used to define coefficients for a
particular I != J type pair, the mixing rule for epsilon and sigma for
all class2 potentials is to use the {sixthpower} formulas documented
by the "pair_modify"_pair_modify.html command. The "pair_modify
mix"_pair_modify.html setting is thus ignored for class2 potentials
for epsilon and sigma. However it is still followed for mixing the
cutoff distance.
:line
Styles with a {cuda}, {gpu}, {intel}, {kk}, {omp}, or {opt} suffix are
functionally the same as the corresponding style without the suffix.
They have been optimized to run faster, depending on your available
hardware, as discussed in "Section_accelerate"_Section_accelerate.html
of the manual. The accelerated styles take the same arguments and
should produce the same results, except for round-off and precision
issues.
These accelerated styles are part of the USER-CUDA, GPU, USER-INTEL,
KOKKOS, USER-OMP and OPT packages, respectively. They are only
enabled if LAMMPS was built with those packages. See the "Making
LAMMPS"_Section_start.html#start_3 section for more info.
You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the "-suffix command-line
switch"_Section_start.html#start_7 when you invoke LAMMPS, or you can
use the "suffix"_suffix.html command in your input script.
See "Section_accelerate"_Section_accelerate.html of the manual for
more instructions on how to use the accelerated styles effectively.
:line
[Mixing, shift, table, tail correction, restart, rRESPA info]:
For atom type pairs I,J and I != J, the epsilon and sigma coefficients
and cutoff distance for all of the lj/class2 pair styles can be mixed.
Epsilon and sigma are always mixed with the value {sixthpower}. The
cutoff distance is mixed by whatever option is set by the pair_modify
command (default = geometric). See the "pair_modify" command for
details.
All of the lj/class2 pair styles support the
"pair_modify"_pair_modify.html shift option for the energy of the
Lennard-Jones portion of the pair interaction.
The {lj/class2/coul/long} pair style does not support the
"pair_modify"_pair_modify.html table option since a tabulation
capability has not yet been added to this potential.
All of the lj/class2 pair styles support the
"pair_modify"_pair_modify.html tail option for adding a long-range
tail correction to the energy and pressure of the Lennard-Jones
portion of the pair interaction.
All of the lj/class2 pair styles write their information to "binary
restart files"_restart.html, so pair_style and pair_coeff commands do
not need to be specified in an input script that reads a restart file.
All of the lj/class2 pair styles can only be used via the {pair}
keyword of the "run_style respa"_run_style.html command. They do not
support the {inner}, {middle}, {outer} keywords.
[Restrictions:]
These styles are part of the CLASS2 package. They are only enabled if
LAMMPS was built with that package. See the "Making
LAMMPS"_Section_start.html#start_3 section for more info.
[Related commands:]
"pair_coeff"_pair_coeff.html
[Default:] none
:line
:link(Sun)
[(Sun)] Sun, J Phys Chem B 102, 7338-7364 (1998).
Event Timeline
Log In to Comment