MOLPRO

15 DENSITY FITTING 93
14.2.1 Example for integral-direct calculations
memory,2,m
$method=[hf,mp2,ccsd,qci,bccd,multi,mrci,acpf,rs3]
!some methods
basis=vdz
!basis
geometry={o;h1,o,r;h2,o,r,h1,theta}
!geometry
gdirect
!direct option
r=1 ang,theta=104 !bond length and angle
do i=1,#method
!loop over methods
$method(i)
!run method(i)
e(i)=energy
!save results in variables
dip(i)=dmz
enddo
table,method,e,dip
!print table of results
http://www.molpro.net/info/current/examples/h2o_direct.com
This jobs produces the following table:
METHOD E DIP
HF -76.02145798 0.82747348
MP2 -76.22620591 0.00000000
CCSD -76.23580191 0.00000000
QCI -76.23596211 0.00000000
BCCD -76.23565813 0.00000000
MULTI -76.07843443 0.76283026
MRCI -76.23369819 0.76875001
ACPF -76.23820180 0.76872802
RS3 -76.23549448 0.75869972
15 DENSITY FITTING
Density fitting can be used to approximate the integrals in spin restricted Hartree-Fock (HF),
density functional theory (KS), second-order Møller-Plesset perturbation theory (MP2 and RMP2),
explicitly correlated MP2 (MP2-F12), and all levels of closed-shell local correlation methods
(LCC2, LMP2-LMP4, LQCISD(T), LCCSD(T)). Density fitting is invoked by adding the prefix
DF- to the command name, e.g. DF-HF, DF-KS, DF-MP2 and so on. Gradients are available
for DF-HF, DF-KS, and DF-LMP2. Symmetry is not implemented for density fitting
programs. Therefore, symmetry is turned off automatically if DF- is found in the input.
By default, a fitting basis set will be chosen automatically that corresponds to the current orbital
basis set and is appropriate for the method. For instance, if the orbital basis set is VTZ, the
default fitting basis is VTZ/JKFIT for DF-HF or DF-KS, and VTZ/MP2FIT for DF-MP2.
Other fitting basis sets from the library can be chosen using the DF BASIS option, e.g.
BASIS=VTZ
DF-HF,DF_BASIS=VQZ
DF-MP2,DF_BASIS=VQZ
!use VTZ orbital basis
!use VQZ/JKFIT fitting basis
!use VQZ/MP2FIT fitting basis
The program then chooses automatically the set which is appropriate for the method. Optionally,
the basis type can appended to the basis name and then this supercedes the default, e.g.