angle_quartic.txt
b6e5ec143f67lammm-master-deprecated

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

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

			:line

			angle_style quartic command :h3

			[Syntax:]

			angle_style quartic :pre

			[Examples:]

			angle_style quartic
			angle_coeff 1 129.1948 56.8726 -25.9442 -14.2221 :pre

			[Description:]

			The {quartic} angle style uses the potential

			:c,image(Eqs/angle_quartic.jpg)

			where theta0 is the equilibrium value of the angle, and K is a
			prefactor. Note that the usual 1/2 factor is included in K.

			The following coefficients must be defined for each angle type via the
			"angle_coeff"_angle_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:

			theta0 (degrees)
			K2 (energy/radian^2)
			K3 (energy/radian^3)
			K4 (energy/radian^4) :ul

			Theta0 is specified in degrees, but LAMMPS converts it to radians
			internally; hence the units of K are in energy/radian^2.

			:line

			[Restrictions:]

			This angle style can only be used if LAMMPS was built with the
			USER_MISC package. See the "Making LAMMPS"_Section_start.html#start_3
			section for more info on packages.

			[Related commands:]

			"angle_coeff"_angle_coeff.html

			[Default:] none