lammps/doc/pair_morse.txt

"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 morse command :h3
pair_style morse/cuda command :h3
pair_style morse/gpu command :h3
pair_style morse/opt command :h3

[Syntax:]

pair_style morse cutoff :pre

cutoff = global cutoff for Morse interactions (distance units) :ul

[Examples:]

pair_style morse 2.5
pair_coeff * * 100.0 2.0 1.5
pair_coeff 1 1 100.0 2.0 1.5 3.0 :pre

[Description:]

Style {morse} computes pairwise interactions with the formula

:c,image(Eqs/pair_morse.jpg)

Rc is the cutoff.

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:

D0 (energy units)
alpha (1/distance units)
r0 (distance units)
cutoff (distance units) :ul

The last coefficient is optional.  If not specified, the global morse
cutoff is used.

:line

Styles with a {cuda}, {gpu}, 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 "this section"_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", and "opt"
packages respectively.  They are only enabled if LAMMPS was built with
those packages.  See the "Making LAMMPS"_Section_start.html#2_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#2_6 when you invoke LAMMPS, or you can use
the "suffix"_suffix.html command in your input script.

See "this section"_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]:

None of these pair styles support mixing.  Thus, coefficients for all
I,J pairs must be specified explicitly.

All of these pair styles support the "pair_modify"_pair_modify.html
shift option for the energy of the pair interaction.

The "pair_modify"_pair_modify.html table options is not relevant for
the Morse pair styles.

None of these pair styles support the "pair_modify"_pair_modify.html
tail option for adding long-range tail corrections to energy and
pressure.

All of these 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.

These 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.

:line

[Restrictions:] none

[Related commands:]

"pair_coeff"_pair_coeff.html

[Default:] none