mirror of https://github.com/pfloos/quack
102 lines
3.5 KiB
Fortran
102 lines
3.5 KiB
Fortran
recursive function HRR2e(AngMomBra,AngMomKet, &
|
|
maxm,Om,ExpZi,ExpY, &
|
|
CenterAB,CenterZA,CenterY) &
|
|
result(a1a2b1b2)
|
|
|
|
! Horintal recurrence relations for two-electron integrals
|
|
|
|
implicit none
|
|
include 'parameters.h'
|
|
|
|
! Input variables
|
|
|
|
integer,intent(in) :: AngMomBra(2,3),AngMomKet(2,3)
|
|
integer,intent(in) :: maxm
|
|
double precision,intent(in) :: Om(0:maxm),ExpZi(2),ExpY(2,2)
|
|
double precision,intent(in) :: CenterAB(2,3),CenterZA(2,3),CenterY(2,2,3)
|
|
|
|
! Local variables
|
|
|
|
logical :: NegAngMomKet(2)
|
|
integer :: TotAngMomBra(2),TotAngMomKet(2)
|
|
integer :: a1p(2,3),b1m(2,3),a2p(2,3),b2m(2,3)
|
|
integer :: i,j,xyz
|
|
double precision :: VRR2e
|
|
|
|
! Output variables
|
|
|
|
double precision :: a1a2b1b2
|
|
|
|
do i=1,2
|
|
NegAngMomKet(i) = AngMomKet(i,1) < 0 .or. AngMomKet(i,2) < 0 .or. AngMomKet(i,3) < 0
|
|
TotAngMomBra(i) = AngMomBra(i,1) + AngMomBra(i,2) + AngMomBra(i,3)
|
|
TotAngMomKet(i) = AngMomKet(i,1) + AngMomKet(i,2) + AngMomKet(i,3)
|
|
enddo
|
|
|
|
!------------------------------------------------------------------------
|
|
! Termination condition
|
|
!------------------------------------------------------------------------
|
|
! if(NegAngMomKet(1) .or. NegAngMomKet(2)) then
|
|
! a1a2b1b2 = 0d0
|
|
!------------------------------------------------------------------------
|
|
! 1st and 2nd vertical recurrence relations: <a1a2|00>
|
|
!------------------------------------------------------------------------
|
|
! elseif(TotAngMomKet(1) == 0 .and. TotAngMomKet(2) == 0) then
|
|
if(TotAngMomKet(1) == 0 .and. TotAngMomKet(2) == 0) then
|
|
a1a2b1b2 = VRR2e(0,AngMomBra,maxm,Om,ExpZi,ExpY,CenterZA,CenterY)
|
|
!------------------------------------------------------------------------
|
|
! 1st horizontal recurrence relation (2 terms): <a1a2|b1+0>
|
|
!------------------------------------------------------------------------
|
|
elseif(TotAngMomKet(2) == 0) then
|
|
do i=1,2
|
|
do j=1,3
|
|
a1p(i,j) = AngMomBra(i,j)
|
|
b1m(i,j) = AngMomKet(i,j)
|
|
enddo
|
|
enddo
|
|
! Loop over cartesian directions
|
|
xyz = 0
|
|
if (AngMomKet(1,1) > 0) then
|
|
xyz = 1
|
|
elseif(AngMomKet(1,2) > 0) then
|
|
xyz = 2
|
|
elseif(AngMomKet(1,3) > 0) then
|
|
xyz = 3
|
|
else
|
|
write(*,*) 'xyz = 0 in HRR2e!'
|
|
endif
|
|
! End loop over cartesian directions
|
|
a1p(1,xyz) = a1p(1,xyz) + 1
|
|
b1m(1,xyz) = b1m(1,xyz) - 1
|
|
a1a2b1b2 = HRR2e(a1p,b1m,maxm,Om,ExpZi,ExpY,CenterAB,CenterZA,CenterY) &
|
|
+ CenterAB(1,xyz)*HRR2e(AngMomBra,b1m,maxm,Om,ExpZi,ExpY,CenterAB,CenterZA,CenterY)
|
|
!------------------------------------------------------------------------
|
|
! 2nd horizontal recurrence relation (2 terms): <a1a2|b1b2+>
|
|
!------------------------------------------------------------------------
|
|
else
|
|
do i=1,2
|
|
do j=1,3
|
|
a2p(i,j) = AngMomBra(i,j)
|
|
b2m(i,j) = AngMomKet(i,j)
|
|
enddo
|
|
enddo
|
|
! Loop over cartesian directions
|
|
xyz = 0
|
|
if (AngMomKet(2,1) > 0) then
|
|
xyz = 1
|
|
elseif(AngMomKet(2,2) > 0) then
|
|
xyz = 2
|
|
elseif(AngMomKet(2,3) > 0) then
|
|
xyz = 3
|
|
else
|
|
write(*,*) 'xyz = 0 in HRR2e!'
|
|
endif
|
|
! End loop over cartesian directions
|
|
a2p(2,xyz) = a2p(2,xyz) + 1
|
|
b2m(2,xyz) = b2m(2,xyz) - 1
|
|
a1a2b1b2 = HRR2e(a2p,b2m,maxm,Om,ExpZi,ExpY,CenterAB,CenterZA,CenterY) &
|
|
+ CenterAB(2,xyz)*HRR2e(AngMomBra,b2m,maxm,Om,ExpZi,ExpY,CenterAB,CenterZA,CenterY)
|
|
endif
|
|
|
|
end function HRR2e
|