XCrySDen can
visualize vector-field by arrows.
Technically this
is noting else than the extension of the display of
forces acting on atoms. For this reason the vector
field is specified very similar as atomic forces inside
the
XSF file.
All that is needed to specify the forces acting on
atoms in the
XSF file is
to supplement the appropriate Cartesian coordinates
(ATOMS or PRIMCOORD section) with the three Cartesian
force components:
AtomicSymbol X Y Z Fx Fy Fz
But for the vector fields, the dummy
atoms (labeled as "X") are used. Namely, the dummy
atoms does not have chemical bonds, hence a large
number of dummy atoms can be locates in the close
region.
The display parameters of the vector's field arrows
can be tuned via the Modify->Force Settings
menu (read more),
while the display of the dummy "atoms" can be
modified via the Modify->Atomic Radius
(read more),
and Modify->Atomic
Color (read more) menus for
the radius and color, respectively.
Here is a dummy example of the specification of the
vector field in the XSF file
(first the atomic structure is specified, and then
the vector field by the dummy "X" atoms):
ATOMS
C 0.0000000000 0.0000000000 0.0000000000
O 0.0000000000 0.0000000000 1.2614009982
N 0.0000000000 1.1482466623 -0.6997899990
N 0.0000000000 -1.1482466623 -0.6997899990
H 0.0000000000 2.0265496485 -0.2028169999
H 0.0000000000 -2.0265496485 -0.2028169999
H 0.0000000000 1.1340804828 -1.7049749982
H 0.0000000000 -1.1340804828 -1.7049749982
X 2.000 0.000 2.000 0.010 0.000 0.000
X 1.902 0.618 2.000 0.010 0.003 0.000
X 1.618 1.176 2.000 0.008 0.006 0.000
X 1.176 1.618 2.000 0.006 0.008 0.000
X 0.618 1.902 2.000 0.003 0.010 0.000
X -0.000 2.000 2.000 -0.000 0.010 0.000
X -0.618 1.902 2.000 -0.003 0.010 0.000
X -1.176 1.618 2.000 -0.006 0.008 0.000
X -1.618 1.176 2.000 -0.008 0.006 0.000
X -1.902 0.618 2.000 -0.010 0.003 0.000
X -2.000 -0.000 2.000 -0.010 -0.000 0.000
X -1.902 -0.618 2.000 -0.010 -0.003 0.000
X -1.618 -1.176 2.000 -0.008 -0.006 0.000
X -1.176 -1.618 2.000 -0.006 -0.008 0.000
. . .
And here is how
XCrySDen displays the
vector field (this is merely an "artistic" example):