MOLPRO

17 THE DENSITY FUNCTIONAL PROGRAM 110
17.2.4 Rangehybrid methods (RANGEHYBRID)
For coupling of short-range (sr-)DFT with long-range (lr-)ab-initio methods, one first has to
specify the coupling parameter µ in the sr interelectronic interaction ∑ i< j erf(µr i j )/r i j ; this can
be done by setting a variable (e.g. mu=0.5). As a next step, long-range ERIs have to be
calculated by calling the integral program (e.g. int;erf,mu;).
Then sr-DFT/lr-HF calculations can be performed by calling the RKS program with the additional
subcommand rangehybrid. Available short-range functionals are exerf and ecerf
for sr-LDA, and exerfpbe and ecerfpbe for sr-PBE; as usual, the functionals have to be
specified after the rks command (e.g. rks,exerf,ecerf;). The underlying short-range
LDA correlation functional is that of S. Paziani, S. Moroni, P. Gori-Giorgi, G.B. Bachelet, Phys.
Rev. B 73, 155111 (2006).
Finally, sr-DFT/lr-post-HF calculations can be done by adding, within a call of the chosen post-
HF program, two subcommands: srxcdft followed by the desired short-range functionals
(e.g. srxcdft,exerf,ecerf;), and dftden followed by the record number from which
the density for the sr functionals is taken. Implementations are available for ci, mp2, ccsd,
ccsd(t), and the corresponding local MP2 and CC methods w/wo density-fitting.
17.2.5 Exchange-correlation potential (POTENTIAL)
POTENTIAL,rec.fil
For stand-alone DFT calculations, compute exchange-correlation potential pseudo-matrix elements,
defined formally as the differential of the sum of all specified functionals with respect to
elements of the atomic orbital density matrix. The matrix is written to record rec on file fil.
17.2.6 Grid blocking factor (DFTBLOCK)
DFTBLOCK,nblock
Respecify the number of spatial integration points treated together as a block in the DFT integration
routines (default 128). Increasing nblock may enhance efficiency on, e.g., vector architectures,
but leads to increased memory usage.
17.2.7 Dump integrand values(DFTDUMP)
DFTDUMP,file,status
Write out values of the integrand at grid points to the file file. The first line of file contains
the number of functional components; there then follows a line for each functional giving the
input key of the functional. Subsequent lines give the functional number, cartesian coordinates,
integrand value and integration weight with Fortran format (I2,3F15.10,F23.15).
17.3 Numerical integration grid control (GRID)
Density functionals are evaluated through numerical quadrature on a grid in three-dimensional
space. Although the sensible defaults will usually suffice, the parameters that define the grid
can be specified by using the GRID top-level command, which should be presented before the
the DFT or KS commands that will use the grid. Alternatively, GRID and its subcommands can
be presented as directives within the KS program.