|FIELD||Molecular field specification. The available field acronyms are given in Table 12. This specification is mandatory, even though the syntax is that of an option!|
|BASIS||The Kohn-Sham density is used for the construction of the plot function. This is the default.|
|AUXIS||The auxiliary function density is used for the construction of the plot function. This option is incompatible with the READ option.|
|BINARY||A binary file FIELD.bin is written in VU file format. It contains the coordinates and plot function values. The VU control file deMon.pie is written too. This is the default.|
|ASCII||An ASCII file FIELD.asc is written. It contains the coordinates and plot function values.|
|TABLE||A table with coordinates and plot function values is written to the output file deMon.out.|
|READ||Specifies that an orbital list is read in the keyword body of PLOT. This keyword is incompatible with the EFIDS field.|
|LMO||Localize molecular orbitals by Cholesky decomposition of the density matrix  before molecular fields are calculated. Only meaningful with the BASIS option.|
|FBLMO||Localize molecular orbitals by Foster-Boys method  before molecular fields are calculated. Only meaningful with the BASIS option.|
|PMLMO||Localize molecular orbitals by Pipek-Mezey method  before molecular fields are calculated. Only meaningful with the BASIS option.|
|DD||The deformation density is used for the molecular field calculation.|
The BASIS and AUXIS options specify the density (Kohn-Sham or auxiliary function density, respectively) used for the calculation of the molecular field. The AUXIS option is incompatible with the orbital specification by the READ option. Use of the auxiliary function density for the calculation of the molecular field will yield a considerable speedup. However, the field values may show deviations of as much as 10% compared to the Kohn-Sham density results. Most certainly these deviations depend on the chosen auxiliary function set (see 4.3.3). In general, the field topology obtained with the auxiliary function density is qualitatively correct.
The PLOT keyword produces two additional output files, the binary file FIELD.bin and the VU control file deMon.pie. With these files, a VU  session can be started. With the ASCII option, only the file FIELD.asc is created. The coordinates and molecular field values are listed in this file. With the TABLE option, the output is created but written to the deMon.out output file.
A set of molecular orbitals can be specified with the READ option for the calculation of molecular fields. However, this option cannot be used for the EFIDS field. In the case of the PSI and D1PSI fields, the READ option specifies the calculated molecular orbitals directly. Again, for PSI no more than 20 orbitals at a time can be calculated and, for D1PSI, no more than 5. If orbitals are selected in the case of other fields, then those fields are constructed from the sum of the selected orbitals. For example the following input specifies the calculation of the density using the molecular orbitals 1, 2, and 4:
PLOT RHO READ 1 2 4
Virtual orbitals can be included. They will be occupied by one electron. In the case of an unrestricted calculation (UKS option of keyword SCFTYPE; see 4.5.1), and -orbitals can be selected, each set in a separate input line. In the following example, the -orbitals 1, 2, 3, 4, 5, 6, 7, and the -orbitals 1, 2, 3, 4, 5, 6 are selected for the calculation of the molecular electrostatic potential:
PLOT ESP READ 1 2 3 4 5 6 7 1 2 3 4 5 6
If only the -orbitals are to be selected, the first line in the preceding example must have a 0 entry, as follows:
PLOT ESP READ 0 1 2 3 4 5 6
With the options LMO, FBLMO, and PMLMO the localization of molecular orbitals is requested. These localized orbitals can either be plotted (in combination with the PSI field option) or used for the calculation of molecular fields. Again, fields can be calculated with subsets of localized orbitals. For the electrostatic potential and its derivatives, it is also possible to plot only the electronic part by using minus signs in front of the corresponding field acronyms, i.e. -ESP, -D1ESP, and -D2ESP. Figure 14 depicts some molecular field plots obtained with the PLOT keyword and rendered with VU .
The DD option of the PLOT keyword triggers the use of deformation densities calculated according to Eq. (4.28). The deformation density itself is plotted by:
PLOT RHO DD
With the IMF PLOT option the NICS, the induced magnetic field vectors, and the absolute induced magnetic field values at each point of the grid are calculated. The external magnetic field can be specified with the READ option:
PLOT IMF READ 1.0 0.0 0.0 # Geometry C1 0.000000 1.396400 0.000000 C2 0.000000 0.698200 1.209318 C3 0.000000 -0.698200 1.209318 C4 0.000000 -1.396400 0.000000 C5 0.000000 -0.698200 -1.209318 C6 0.000000 0.698200 -1.209318 H1 0.000000 2.479500 0.000000 H2 0.000000 1.239750 2.147310 H3 0.000000 -1.239750 2.147310 H4 0.000000 -2.479500 0.000000 H5 0.000000 -1.239750 -2.147310 H6 0.000000 1.239750 -2.147310
In this example the external field is oriented along the -axis which is perpendicular to the benzene molecule defined in the -plane. By default the external magnetic field is oriented along the -axis.