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5.10 Asymptotically Corrected Exchange-Correlation Potentials

5.10.3 Localized Fermi-Amaldi (LFA) Schemes

(April 13, 2024)

Another alternative, proposed by Pan, Fang and Chai, 929 Pan C.-R., Fang P.-T., Chai J.-D.
Phys. Rev. A
(2013), 87, pp. 052510.
Link
is to use a localized version of Fermi-Amaldi exchange-correlation functional. The resulting exchange density functional, whose functional derivative has the correct -1/r asymptotic behavior, can be directly added to any semi-local density functional. Three variants of this method were proposed in Ref.  929 Pan C.-R., Fang P.-T., Chai J.-D.
Phys. Rev. A
(2013), 87, pp. 052510.
Link
. The simplest of these, the strictly-localized Fermi-Amaldi (LFAs) scheme, is implemented in Q-Chem, for molecules consisting of atoms with Z55.

Example 5.22  LFAs-PBE single-point TD-DFT calculation with water molecule

$comment
   Use LFAs-PBE potential for ground-state calculations, followed by
   TDDFT calculations with an adiabatic PBE XC kernel.
$end

$molecule
   0  1
   O
   H1  O  oh
   H2  O  oh  H1  hoh

   oh  =   1.0
   hoh = 110.0
$end

$rem
   EXCHANGE      gen
   BASIS         6-311(2+,2+)G**
   CIS_N_ROOTS   30
   RPA           true
$end

$xc_functional
   X   PBE   1.0
   C   PBE   1.0
   X   LFAs  1.0
$end