mirror of
https://github.com/pfloos/quack
synced 2024-06-28 08:02:24 +02:00
92 lines
1.9 KiB
Fortran
92 lines
1.9 KiB
Fortran
subroutine RGIC_lda_exchange_derivative_discontinuity(nEns,wEns,nGrid,weight,rhow,ExDD)
|
|
|
|
! Compute the restricted version of the GIC exchange individual energy
|
|
|
|
implicit none
|
|
include 'parameters.h'
|
|
|
|
! Input variables
|
|
|
|
integer,intent(in) :: nEns
|
|
double precision,intent(in) :: wEns(nEns)
|
|
integer,intent(in) :: nGrid
|
|
double precision,intent(in) :: weight(nGrid)
|
|
double precision,intent(in) :: rhow(nGrid)
|
|
|
|
! Local variables
|
|
|
|
integer :: iEns,jEns
|
|
integer :: iG
|
|
double precision :: r
|
|
double precision,allocatable :: dExdw(:)
|
|
double precision,external :: Kronecker_delta
|
|
|
|
double precision :: a,b,c,w
|
|
double precision :: dCxGICdw
|
|
|
|
! Output variables
|
|
|
|
double precision,intent(out) :: ExDD(nEns)
|
|
|
|
! Memory allocation
|
|
|
|
allocate(dExdw(nEns))
|
|
|
|
! Compute correlation energy for ground- and doubly-excited states
|
|
|
|
|
|
! Parameters for H2 at equilibrium
|
|
|
|
! a = + 0.5751782560799208d0
|
|
! b = - 0.021108186591137282d0
|
|
! c = - 0.36718902716347124d0
|
|
|
|
! Parameters for stretch H2
|
|
|
|
! a = + 0.01922622507087411d0
|
|
! b = - 0.01799647558018601d0
|
|
! c = - 0.022945430666782573d0
|
|
|
|
! Parameters for He
|
|
|
|
! a = 1.9125735895875828d0
|
|
! b = 2.715266992840757d0
|
|
! c = 2.1634223380633086d0
|
|
|
|
! Parameters for HNO
|
|
|
|
a = 0.0061158387543040335d0
|
|
b = -0.00005968703047293955d0
|
|
c = -0.00001692245714408755d0
|
|
|
|
w = wEns(2)
|
|
dCxGICdw = (0.5d0*b + (2d0*a + 0.5d0*c)*(w - 0.5d0) - (1d0 - w)*w*(3d0*b + 4d0*c*(w - 0.5d0)))
|
|
dCxGICdw = CxLDA*dCxGICdw
|
|
|
|
dExdw(:) = 0d0
|
|
|
|
do iG=1,nGrid
|
|
|
|
r = max(0d0,rhow(iG))
|
|
|
|
if(r > threshold) then
|
|
|
|
dExdw(1) = 0d0
|
|
dExdw(2) = dExdw(2) + weight(iG)*dCxGICdw*r**(4d0/3d0)
|
|
|
|
end if
|
|
|
|
end do
|
|
|
|
ExDD(:) = 0d0
|
|
|
|
do iEns=1,nEns
|
|
do jEns=2,nEns
|
|
|
|
ExDD(iEns) = ExDD(iEns) + (Kronecker_delta(iEns,jEns) - wEns(jEns))*dExdw(jEns)
|
|
|
|
end do
|
|
end do
|
|
|
|
end subroutine RGIC_lda_exchange_derivative_discontinuity
|