63 lines
1.6 KiB
Plaintext
63 lines
1.6 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,Commands_all.html)
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:line
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angle_style cross command :h3
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[Syntax:]
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angle_style cross :pre
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[Examples:]
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angle_style cross
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angle_coeff 1 200.0 100.0 100.0 1.25 1.25 107.0 :pre
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[Description:]
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The {cross} angle style uses a potential that couples the bond stretches of
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a bend with the angle stretch of that bend:
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:c,image(Eqs/angle_cross.jpg)
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where r12,0 is the rest value of the bond length between atom 1 and 2,
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r32,0 is the rest value of the bond length between atom 2 and 2,
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and theta0 is the rest value of the angle. KSS is the force constant of
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the bond stretch-bond stretch term and KBS0 and KBS1 are the force constants
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of the bond stretch-angle stretch terms.
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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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KSS (energy/distance^2)
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KBS0 (energy/distance/rad)
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KBS1 (energy/distance/rad)
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r12,0 (distance)
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r32,0 (distance)
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theta0 (degrees) :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 KBS0 and KBS1 are in energy/distance/radian.
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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_YAFF package. See the "Build package"_Build_package.html doc
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page for more info.
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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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:line
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