trappe1998.lt
12150ffa7397lammm-devel

trappe1998.lt
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			# This file stores complete LAMMPS data for the TraPPE model of saturated
			# hydrocarbon chains. In this "united-atom" model, each methyl group is
			# represented by a single atom. Forces between "atoms" are taken from the
			# TraPPE force-field. (J Phys Chem B, 1998, volume 102, pp.2569-2577)

			TraPPE {

			write_once("In Init") {
			# -- Default styles for "TraPPE" --
			units real
			atom_style full
			# (Hybrid force field styles were used for portability.)
			bond_style hybrid harmonic
			angle_style hybrid harmonic
			dihedral_style hybrid opls
			improper_style none
			pair_style hybrid lj/charmm/coul/charmm 9.0 11.0 9.0 11.0
			pair_modify mix arithmetic
			special_bonds lj 0.0 0.0 0.0
			}

			write_once("Data Masses") {
			@atom:CH2 14.1707
			@atom:CH3 15.2507
			@atom:CH4 16.3307
			}

			write_once("Data Angles By Type") {
			@angle:backbone @atom:CH? @atom:CH? @atom:CH? @bond:saturated @bond:saturated
			}

			write_once("Data Dihedrals By Type") {
			@dihedral:backbone @atom:CH? @atom:CH? @atom:CH? @atom:CH? @bond:saturated @bond:saturated @bond:saturated
			}

			write_once("In Settings") {
			pair_coeff @atom:CH2 @atom:CH2 lj/charmm/coul/charmm 0.091411522 3.95
			pair_coeff @atom:CH3 @atom:CH3 lj/charmm/coul/charmm 0.194746286 3.75
			pair_coeff @atom:CH4 @atom:CH4 lj/charmm/coul/charmm 0.294106636 3.73
			bond_coeff @bond:saturated harmonic 120.0 1.54
			angle_coeff @angle:backbone harmonic 62.0022 114
			dihedral_coeff @dihedral:backbone opls 1.411036 -0.271016 3.145034 0.0
			}

			write_once("In Settings") {
			group TraPPE type @atom:CH2 @atom:CH3 @atom:CH4
			}

			} # class TraPPE