Release66:DPLOT

__NOTITLE__
=DPLOT=

  DPLOT
    ...
  END

This directive is used to obtain the plots of various types of electron densities (or orbitals) of the molecule. The electron density is calculated on a specified set of grid points using the molecular orbitals from SCF or DFT calculation. The output file is either in MSI Insight II contour format (default) or in the Gaussian Cube format. DPLOT is not executed until the "task dplot" directive is given. Different sub-directives are described below.

The implementation of the dplot functionality uses mostly local memory. The quantities stored in local memory are:
* the positions of the grid points
* the property of interest expressed at the grid points
The stack memory setting in the input file must be sufficient to hold these quantities in local memory on a processor.

==GAUSSIAN -- Gaussian Cube format==

  GAUSSIAN

A outputfile is generate in Gaussian Cube format. You can visualize this file using gOpenMol (after converting the Gaussian Cube file with gcube2plt), Molden or Molekel.

==TITLE -- Title directive==

  TITLE <string Title default Unknown Title>

This sub-directive specifies a title line for the generated input to the Insight program or for the Gaussian cube file. Only one line is allowed.

==LIMITXYZ -- Plot limits==

  LIMITXYZ [units <string Units default angstroms>]
  <real X_From> <real X_To> <integer No_Of_Spacings_X>
  <real Y_From> <real Y_To> <integer No_Of_Spacings_Y>
  <real Z_From> <real Z_To> <integer No_Of_Spacings_Z>

This sub-directive specifies the limits of the cell to be plotted. The grid is generated using No_Of_Spacings + 1 points along each direction. The known names for Units are angstroms, au and bohr.

==SPIN -- Density to be plotted==

  SPIN <string Spin default total>

This sub-directive specifies, what kind of density is to be computed. The known names for Spin are total, alpha, beta and spindens, the last being computed as the difference between &alpha; and &beta; electron densities.

==OUTPUT -- Filename==

  OUTPUT <string File_Name default dplot>

This sub-directive specifies the name of the generated input to the Insight program or the generated Gaussian cube file. The name OUTPUT is reserved for the standard NWChem output.

==VECTORS -- MO vector file name==

  VECTORS <string File_Name default movecs> [<string File_Name2>]

This sub-directive specifies the name of the molecular orbital file. If the second file is optionally given the density is computed as the difference between the corresponding electron densities. The vector files have to match.

==WHERE -- Density evaluation==

  WHERE <string Where default grid>

This sub-directive specifies where the density is to be computed. The known names for Where are grid (the calculation of the density is performed on the set of a grid points specified by the sub-directive LimitXYZ and the file specified by the sub-directive Output is generated), nuclei (the density is computed at the position of the nuclei and written to the NWChem output) and g+n (both).

==ORBITAL -- Orbital sub-space==

  ORBITALS [<string Option default density>]
  <integer No_Of_Orbitals>
  <integer Orb_No_1 Orb_No_2 ...>

This sub-directive specifies the subset of the orbital space for the calculation of the electron density. The density is computed using the occupation numbers from the orbital file modified according to the Spin directive. If the contours of the orbitals are to be plotted Option should be set to <tt>view</tt> (instead of the implicit default value <tt>density</tt>). Note, that in this case No_Of_Orbitals should be set to 1 and sub-directive Where is automatically set to grid. Also specification of two orbital files conflicts with the view option. alpha orbitals are always plotted unless Spin is set to beta.

== CIVECS -- CI vectors ==
CIVECS [<string Name of civecs file>]

== DENSMAT -- Density matrix ==
DENSMAT [<string Name of density matrix file>]

==Examples==

===Charge Density===

Example of charge density plot (with Gaussian Cube output):

 start n2
 geometry
   n  0 0   0.53879155
   n  0 0  -0.53879155
 end
 basis;  n library cc-pvdz;end
 scf
 vectors  output n2.movecs
 end
 dplot
   TITLE HOMO
   vectors n2.movecs
    LimitXYZ
  -3.0 3.0 10  
  -3.0 3.0 10 
  -3.0  3.0  10
   spin total
   gaussian
   output chargedensity.cube
 end
 task scf     
 task dplot

===Molecular Orbital===

Example of orbital plot (with Insight II contour output):

 start n2
 geometry
   n  0 0   0.53879155
   n  0 0  -0.53879155
 end
 basis;  n library cc-pvdz;end
 scf
 vectors  output n2.movecs
 end
 dplot
   TITLE HOMO
   vectors n2.movecs
    LimitXYZ
  -3.0 3.0 10  
  -3.0 3.0 10 
  -3.0  3.0  10
   spin total
   orbitals view; 1; 7
   output homo.grd
 end
 task scf     
 task dplot

=== Transition Density ===

TDDFT calculation followed by a calculation of the transition density for a specific excited state using the DPLOT block

 echo
 start h2o-td
 title h2o-td
 memory total 800 stack 400 heap 50 global 350 mb
 charge 0
 geometry units au noautoz nocenter
 symmetry group c1
  O    0.00000000000000      0.00000000000000      0.00000000000000
  H    0.47043554760291      1.35028113274600      1.06035416576826
  H   -1.74335410533480     -0.23369304784300      0.27360785442967
 end
 basis "ao basis" print
  H    S
     13.0107010              0.19682158E-01
      1.9622572              0.13796524
      0.44453796             0.47831935
  H    S
      0.12194962             1.0000000
  H    P
      0.8000000              1.0000000
  O    S
   2266.1767785             -0.53431809926E-02
    340.87010191            -0.39890039230E-01
     77.363135167           -0.17853911985
     21.479644940           -0.46427684959
      6.6589433124          -0.44309745172
  O    S
      0.80975975668          1.0000000
  O    S
      0.25530772234          1.0000000
  O    P
     17.721504317            0.43394573193E-01
      3.8635505440           0.23094120765
      1.0480920883           0.51375311064
  O    P
      0.27641544411          1.0000000
  O    D
      1.2000000              1.0000000
 end
 dft
  xc bhlyp
  grid fine
  direct
  convergence energy 1d-5
 end
 tddft
  rpa
  nroots 5
  thresh 1d-5
  singlet
  notriplet
  civecs
 end
 task tddft energy
 dplot
  civecs h2o-td.civecs_singlet
  root 2
  LimitXYZ
   -3.74335 2.47044 50
   -2.23369 3.35028 50
   -2 3.06035 50
    gaussian
    output root-2.cube
 end
 task dplot

=== Plot the excited state density ===

 echo
 start tddftgrad_co_exden
 geometry
  C     0.00000000     0.00000000    -0.64628342
  O     0.00000000     0.00000000     0.48264375
  symmetry c1
 end
 basis spherical
  * library "3-21G"
 end
 dft
  xc pbe0
  direct
 end
 tddft
  nroots 3
  notriplet
  target 1
  civecs
  grad
   root 1
  end
 end
 task tddft gradient
 dplot
  densmat tddftgrad_co_exden.dmat
  LimitXYZ
 -4.0 4.0 50
 -4.0 4.0 50
 -4.0 4.0 50
  gaussian
  output co_exden.cube
 end
 task dplot