"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Commands_all.html)

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bond_style mm3 command :h3

[Syntax:]

bond_style mm3 :pre

[Examples:]

bond_style mm3
bond_coeff 1 100.0 107.0 :pre

[Description:]

The {mm3} bond style uses the potential that is anharmonic in the bond
as defined in "(Allinger)"_#mm3-allinger1989

:c,image(Eqs/bond_mm3.jpg)

where r0 is the equilibrium value of the bond, and K is a
prefactor. The anharmonic prefactors have units angstrom^(-n):
-2.55 angstrom^(-1) and (7/12)2.55^2 angstrom^(-2). The code takes
care of the necessary unit conversion for these factors internally.
Note that the MM3 papers contains an error in Eq (1):
(7/12)2.55 should be replaced with (7/12)2.55^2

The following coefficients must be defined for each bond type via the
"bond_coeff"_bond_coeff.html command as in the example above, or in
the data file or restart files read by the "read_data"_read_data.html
or "read_restart"_read_restart.html commands:

K (energy/distance^2)
r0 (distance) :ul

[Restrictions:]

This bond style can only be used if LAMMPS was built with the
USER_YAFF package.  See the "Build package"_Build_package.html doc
page for more info.

[Related commands:]

"bond_coeff"_bond_coeff.html

[Default:] none

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:link(mm3-allinger1989)
[(Allinger)] Allinger, Yuh, Lii, JACS, 111(23), 8551-8566
(1989),
