MOLPRO

34 PROPERTIES AND EXPECTATION VALUES 266
Compute the density and, optionally, its gradient and laplacian. ¡density-source¿ may be a
record number containing the required density, and may contain further qualification, such as
set number, in the usual way. By default, the last computed density is taken.
34.7.3 ORBITAL — source of orbitals
ORBITAL,[orbital-list],[RECORD=orbital-source]
¡orbital-list¿ is a list of one or more orbital numbers of the form number.symmetry or keywords
chosen from HOMO, LUMO, OCC (all occupied orbitals), ALL. If nothing is specified, the default
is HOMO. ¡orbital-source¿ may be a record number containing the required density, and may
contain further qualification, such as set number, in the usual way. By default, the last computed
orbitals are taken.
Note that the CUBE file format precludes simultaneous orbital and density dumps, but that this
may be achieved in the GOPENMOL format (see 34.8).
34.7.4 AXIS — direction of grid axes
AXIS,x,y,z
x,y,z specify the unnormalised direction cosines of one of the three axes defining the grid. Up
to three AXIS commands can be given, but none is required. Axes need not be orthogonal. By
default, the first axis is the cartesian x, the second is orthogonal to the first and to the cartesian
z, and the third is orthogonal to the first two.
34.7.5 BRAGG — spatial extent of grid
Based on the direction of the coordinate axes, a parallelopiped (in the usual case of orthogonal
axes, a cuboid) is constructed to contain the molecule completely. The atoms are assumed to be
spherical, with an extent proportional to their Bragg radii, and the constant of proportionality
can be changed from the default value using
BRAGG,scale
After the parallelopiped has been constructed, the grid is laid out with equal spacing to cover it
using the number of points specified on the CUBE command.
34.7.6 ORIGIN — centroid of grid
ORIGIN,x,y,z
x,y,z specify the centroid of the grid. It is usually not necessary to use this option, since the
default should suffice for most purposes.
34.7.7 TITLE — user defined title
TITLE,title
Set a user defined title in the cube file.