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Added hexatic bond orientational order parameter 

git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@14238 f3b2605a-c512-4ea7-a41b-209d697bcdaa
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athomps 2015-11-05 16:41:14 +00:00
parent fa9af07140
commit f71eee1d4d
1 changed files with 7 additions and 5 deletions
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12
doc/compute_hexorder_atom.txt
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@ -44,11 +44,13 @@ Neighbor atoms not in the group
are included in the order parameter of atoms in the group.
The optional keyword {n} sets the degree of the order parameter.
The default value is 6. If the neighbors of the central atom
lie on a hexagonal lattice, then |{q}6| = 1.
The complex phase of {q}6 depends on the orientation of the
lattice relative to the {x} axis. For a liquid in which the
atomic neighborhood lacks orientational symmetry, |{q}6| << 1.
The default value is 6. For a perfect hexagonal lattice,
{q}6 = exp(6 i phi) for all atoms, where the constant 0 < phi < pi/3
depends only on the orientation of the lattice relative to the x axis.
In an isotropic liquid, local neighborhoods may still exhibit
weak hexagonal symmetry, but because the orientational correlation
decays quickly with distance, the value of phi will be different for
different atoms, and |<{q}6>| << 1.
The value of {qn} will be zero for atoms not in the
specified compute group. If the atom has less than {n} neighbors (within