forked from lijiext/lammps
55 lines
1.3 KiB
Plaintext
55 lines
1.3 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 quartic command :h3
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[Syntax:]
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angle_style quartic :pre
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[Examples:]
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angle_style quartic
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angle_coeff 1 129.1948 56.8726 -25.9442 -14.2221 :pre
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[Description:]
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The {quartic} angle style uses the potential
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:c,image(Eqs/angle_quartic.jpg)
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where theta0 is the equilibrium value of the angle, and K is a
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prefactor. 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, 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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theta0 (degrees)
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K2 (energy/radian^2)
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K3 (energy/radian^3)
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K4 (energy/radian^4) :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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:line
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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_MISC package. See the "Making LAMMPS"_Section_start.html#start_3
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section for more info on packages.
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[Related commands:]
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"angle_coeff"_angle_coeff.html
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[Default:] none
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