forked from lijiext/lammps
61 lines
1.8 KiB
Plaintext
61 lines
1.8 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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angle_style cg/cmm command :h3
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[Syntax:]
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angle_style cg/cmm :pre
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[Examples:]
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angle_style cg/cmm
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angle_coeff 1 300.0 107.0 lj9_6 0.4491 3.7130 :pre
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[Description:]
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The {cg/cmm} angle style is a combination of the harmonic angle potential,
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:c,image(Eqs/angle_harmonic.jpg)
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where theta0 is the equilibrium value of the angle and K a prefactor,
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with the {repulsive} part of the non-bonded {cg/cmm} pair style
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between the atoms 1 and 3. This angle potential is intended for
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coarse grained MD simulations with the CMM parametrization using the
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"pair_style cg/cmm"_pair_cmm.html. Relative to the pair_style
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{cg/cmm}, however, the energy is shifted by {epsilon}, to avoid sudden
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jumps. Note that the usual 1/2 factor is included in K.
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The following coefficients must be defined for each angle type via the
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"angle_coeff"_angle_coeff.html command as in the example above. As
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with other CMM coarse grained parameters, they cannot be set in the
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data file, but can be restored from restarts via the
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"read_restart"_read_restart.html command:
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K (energy/radian^2)
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theta0 (degrees)
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cg_type (string, one of lj9_6, lj12_4, lj12_6)
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epsilon (energy units)
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sigma (distance units) :ul
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Theta0 is specified in degrees, but LAMMPS converts it to radians
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internally; hence the units of K are in energy/radian^2.
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[Restrictions:]
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This angle style can only be used if LAMMPS was built with the
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"user-cg-cmm" package. See the "Making LAMMPS"_Section_start.html#2_3 section
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for more info on packages.
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[Related commands:]
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"angle_coeff"_angle_coeff.html, "angle_style
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harmonic"_angle_harmonic.html, "pair_style cg/cmm"_pair_cmm.html
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[Default:] none
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