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GRID_IT is an interface program for calculations of molecular
orbitals and density in a set of Cartesian grid points. The calculated grid
can be visualized by LUSCUS program.
The GRID_IT program requires the communication file RUNFILE,
produced by GATEWAY and an orbital file INPORB: SCFORB,
RASORB, PT2ORB, generated by program SCF(calculated with RHF or UHF hamiltonian), RASSCF,
or CASPT2, respectively.
Below is a list of the files that are used/created by the program
|RUNFILE||File for communication of auxiliary information generated by the program
|INPORB||SCFORB or another orbitals file (RASORB, CIORB,
CPFORB, SIORB, PT2ORB) containing calculated orbitals.
If used after SCF run, the information about one-electron
energies is also retrieved.
|LUS||Output file in LUSCUS format, with default extension .lus -- the only file needed
for drawing program. In the case of
UHF calculation, GRID_IT produces two files: a.lus and
b.lus with grids for alpha and beta electrons.
LUSCUS code could be used to combine grid files
for visualization of total or spin density.
|GRID||Obsolete format of the grid file, can be converted to Cube files using
the grid2cube tool. In order to generate a file with data
written in grid format, keyword NOLUSCUS should be used.
Normally, it is no reason to change any default setting of calculated
grid - the choice of appropriate grid size, net frequency, as well as
choice of MO can be done automatically.
If user did not specified the selection of orbitals, GRID_IT
makes a decision based on information in the InpOrb file. For example,
if InpOrb contains data after SCF calculation, a set of orbitals
around HOMO-LUMO gap will be used. If InpOrb contains active orbitals,
they will be used as a default set.
Below follows a description of the input to GRID_IT. The keywords
are always significant to four characters, but in order to make the
input more transparent, it is recommended to use the full keywords.
The GRID_IT program section of the MOLCAS input starts with the
standard reference to the code:
Argument(s) to a keyword are always supplied on the next line of the
input file, except when explicitly stated otherwise.
|TITLe||One line following this one is regarded as title.
|NAME||One line following this one is used for generation of
grid filename in the form: ``Project.Name.lus''.
|FILE||On the following line user can specify the filename, which will be
used instead of INPORB (default). For example: FileOrb=$CurrDir/$Project.ScfOrb.
|SPARse||Set up sparse Cartesian net with 1 grid point per a.u.
Note that quality of the grid can be poor.
Default (without Sparse or Dense) is 3 points per a.u.
|DENSe||Set up net with 10 grid points per a.u. Note that using this option
without choice of orbitals to draw you can produce very large output file.
|GAP||Keyword, followed by real equals to distance between
the atomic nuclei in the molecule and the border of grid.
Default value is 4.0 a.u.
|ORBItal||Direct specification of orbitals to show. Next line set up
number of calculated grids. And at next line(s) pairs of integers - symmetry
and orbital within this symmetry is given.
|SELEct||Direct specification of orbitals to show. Follows by one line
in the format: symmetry:first_orbital-last_orbital
(Ex: 1:2-7 2:5-8)
|MULLiken||Compute Mulliken charges separately for each occupied MO specified in
the GRID_IT input. "LONG print" is an optional argument for more
|NoSort||Do not sort orbitals by occupation numbers and orbital energies
|ORANge||Followed by 2 numbers, to limit the interval of
orbitals by occupation numbers.
|ERANge||Followed by 2 numbers, to limit the interval of
orbitals by one-electron energies
|ALL||Calculate grids for all molecular orbitals. Using this keyword you can produce a
huge output file!
|TOTAl||Request to calculate a grid for the (correct) total
density computed from contributions of all orbitals, instead of (default)
just from the orbitals chosen by user.
|VB||This keyword enables plotting of the orbitals from the latest CASVB orbitals.
Note that the appropriate RASORB orbitals must be available in the INPORB file.
|ATOM||Calculate density at the position of atoms.
|ASCII||Obsolete keyword for ASCII format of output file. This option can only
be used in combination with NOLUSCUS.
This keyword is useful if a calculation
of the grid file and visualization should be done on computers with
|NPOInts||Keyword, followed by 3 integers equal to number of grid points
in x, y, z directions. Using for non-automatic choice of grid network.
|GRID||Keyword to set manually coordinates of a grid. Followed by number of
Cartesian coordinates, and on next lines - x y z coordinates of
a grid (in a.u.)
|GORI||Keyword to set manually the parallelepiped spanning a grid.
Followed by four lines of three columns each.
The first line defines the x y z location of the origin,
the next three lines are three linearly independent vectors
that span the parallelepiped of the grid.
This keyword requires NPOINTS to build up the lattice of gridpoints.
|NOLUSCUS||Produce data file in obsolete format (which can be read by old
(before 2015) versions of GV).
|XFIELD||Use Grid_It it in a special mode (to produce the grid for non-cartesian points).
An example for high quality picture, containing selected orbitals (from symmetry 1 and 4):
An example for screen quality picture, containing all orbitals:
An example for selection orbitals with partial occupation
ORange = 0.01 1.99
Program Grid_it also can do simple arithmetic operations with produces luscus files. In this case the input is different from the described above.
User have to specify two compusory keywords (LUS1 and LUS2) with teh file name as a parameter, and an operation PLUS or MINUS (the latter is default). It is also possible to specify a name of the output file by using keyword name.
An example. The first two runs generate two luscus files: $Project.STO.lus and $Project.ANO.lus , which later are transformed into the third file: $Project.Difference.lus
Next: 8.20 guessorb
Up: 8. Programs
Previous: 8.18 geo