forked from lijiext/lammps
66 lines
1.7 KiB
Plaintext
66 lines
1.7 KiB
Plaintext
"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
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:link(lws,http://lammps.sandia.gov)
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:link(ld,Manual.html)
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:link(lc,Section_commands.html#comm)
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:line
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bond_style fene/expand command :h3
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[Syntax:]
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bond_style fene/expand :pre
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[Examples:]
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bond_style fene/expand
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bond_coeff 1 30.0 1.5 1.0 1.0 0.5 :pre
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[Description:]
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The {fene/expand} bond style uses the potential
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:c,image(Eqs/bond_fene_expand.jpg)
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to define a finite extensible nonlinear elastic (FENE) potential
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"(Kremer)"_#Kremer, used for bead-spring polymer models. The first
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term is attractive, the 2nd Lennard-Jones term is repulsive.
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The {fene/expand} bond style is similar to {fene} except that an extra
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shift factor of delta (positive or negative) is added to {r} to
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effectively change the bead size of the bonded atoms. The first term
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now extends to R0 + delta and the 2nd term is cutoff at 2^(1/6) sigma
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+ delta.
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The following coefficients must be defined for each bond type via the
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"bond_coeff"_bond_coeff.html command as in the example above, or in
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the data file or restart files read by the "read_data"_read_data.html
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or "read_restart"_read_restart.html commands:
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K (energy/distance^2)
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R0 (distance)
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epsilon (energy)
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sigma (distance)
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delta (distance) :ul
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[Restrictions:]
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Bond styles can only be set for atom styles that allow bonds to be
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defined.
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This bond style is part of the "molecular" package. It is only
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enabled if LAMMPS was built with that package. See the "Making
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LAMMPS"_Section_start.html#2_2 section for more info.
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[Related commands:]
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"bond_coeff"_bond_coeff.html, "delete_bonds"_delete_bonds.html
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[Default:] none
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:line
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:link(Kremer)
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[(Kremer)] Kremer, Grest, J Chem Phys, 92, 5057 (1990).
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