MOLPRO

17 THE DENSITY FUNCTIONAL PROGRAM 108
17 THE DENSITY FUNCTIONAL PROGRAM
Density-functional theory calculations may be performed using one of the following commands:
DFT
RKS or RKS-SCF
UKS or UKS-SCF
calculate functional of a previously computed density.
calls the spin-restricted Kohn-Sham program. KS and KS-SCF
are aliases for RKS.
calls the spin-unrestricted Kohn-Sham program
Each of these commands may be qualified with the key-names of the functional(s) which are to
be used, and further options:
command, key1, key2, key3, ..., options
If no functional keyname is given, the default is LDA (see below). Following this command may
appear directives specifying options for the density-functional modules (see section 17.2) or the
Hartree-Fock program (see section 16.1).
On completion of the functional evaluation, or self-consistent Kohn-Sham calculation, the values
of the individual functionals are stored in the MOLPRO vector variable DFTFUNS; the total
is in DFTFUN, and the corresponding individual functional names in DFTNAME.
Energy gradients are available for self-consistent Kohn-Sham calculations.
Density fitting can be used for closed and open-shell spin-restricted KF and is involked by a
prefix DF- (DF-KS or DF-RKS, see section 15). For UKS, only Coulomb fitting is possible
(CF-UKS). Density fitting very much speeds up calculations for large molecules. The greatest
savings are seen for large basis sets with high angular momentum functions. For details see R.
Polly, H.-J. Werner, F. R. Manby, and Peter J. Knowles, Fast Hartree-Fock theory using local
density fitting approximations, Mol. Phys. 102, 2311 (2004). All publications resulting from
DF-HF or DF-KS calculations should cite this work.
Normally, sensible defaults are used to define the integration grid. The accuracy can be controlled
using options as described in section 17.1 or directives as described in section 17.2).
More control is provided by the GRID command, as described in section 17.3.
17.1 Options
The following options may be specified on the KS or UKS command lines:
GRID=target
COARSE (logical)
GRIDMAX=gridmax
Specifies the grid target accuracy (per atom). The default is
1.d-6 unless this has been modeified using a global THRESH,
GRID option.
If true, perform initial iterations with a coarser grid. Default is
false.
In the initial iterations, the grid accuracy is min(gridmax, target*coarsefac)
(only if COARSE is set).
COARSEFAC=coarsefac Factor for initial grid accuracy (see above). The default is 1000.
DFTFAC=[fac1,fac2,..]
EXFAC=factor
Factors for each functional. The number of given values must
agree with the number of functionals.
Fraction of exact exchange added to the functional. The default
depends on the functional.