mirror of https://github.com/pfloos/quack
129 lines
4.6 KiB
Fortran
129 lines
4.6 KiB
Fortran
recursive function HRR3e(AngMomBra,AngMomKet,maxm,Om,ExpZ,CenterAB,CenterZA,DY0,DY1,D2Y0,D2Y1) &
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result(a1a2a3b1b2b3)
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! Horizontal recurrence relations for three-electron integrals
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implicit none
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include 'parameters.h'
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! Input variables
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integer,intent(in) :: AngMomBra(3,3),AngMomKet(3,3)
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integer,intent(in) :: maxm
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double precision,intent(in) :: Om(0:maxm),ExpZ(3),CenterAB(3,3),CenterZA(3,3)
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double precision,intent(in) :: DY0(3),DY1(3),D2Y0(3,3),D2Y1(3,3)
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! Local variables
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logical :: NegAngMomKet(3)
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integer :: TotAngMomBra(3),TotAngMomKet(3)
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integer :: a1p(3,3),b1m(3,3),a2p(3,3),b2m(3,3),a3p(3,3),b3m(3,3)
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integer :: i,j,xyz
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double precision :: VRR3e
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! Output variables
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double precision :: a1a2a3b1b2b3
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do i=1,3
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NegAngMomKet(i) = AngMomKet(i,1) < 0 .or. AngMomKet(i,2) < 0 .or. AngMomKet(i,3) < 0
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TotAngMomBra(i) = AngMomBra(i,1) + AngMomBra(i,2) + AngMomBra(i,3)
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TotAngMomKet(i) = AngMomKet(i,1) + AngMomKet(i,2) + AngMomKet(i,3)
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enddo
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!------------------------------------------------------------------------
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! Termination condition
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!------------------------------------------------------------------------
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if(NegAngMomKet(1) .or. NegAngMomKet(2) .or. NegAngMomKet(3)) then
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a1a2a3b1b2b3 = 0d0
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!------------------------------------------------------------------------
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! 1st and 2nd vertical recurrence relations: <a1a2a3|000>
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!------------------------------------------------------------------------
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elseif(TotAngMomKet(1) == 0 .and. TotAngMomKet(2) == 0 .and. TotAngMomKet(3) == 0) then
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a1a2a3b1b2b3 = VRR3e(0,AngMomBra,maxm,Om,ExpZ,CenterZA,DY0,DY1,D2Y0,D2Y1)
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!------------------------------------------------------------------------
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! 1st horizontal recurrence relation (2 terms): <a1a2a3|b1+00>
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!------------------------------------------------------------------------
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elseif(TotAngMomKet(2) == 0 .and. TotAngMomKet(3) == 0) then
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do i=1,3
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do j=1,3
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a1p(i,j) = AngMomBra(i,j)
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b1m(i,j) = AngMomKet(i,j)
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enddo
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enddo
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! Loop over cartesian directions
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xyz = 0
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if (AngMomKet(1,1) > 0) then
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xyz = 1
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elseif(AngMomKet(1,2) > 0) then
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xyz = 2
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elseif(AngMomKet(1,3) > 0) then
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xyz = 3
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else
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write(*,*) 'xyz = 0 in HRR3e!'
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endif
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! End loop over cartesian directions
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a1p(1,xyz) = a1p(1,xyz) + 1
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b1m(1,xyz) = b1m(1,xyz) - 1
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a1a2a3b1b2b3 = HRR3e(a1p,b1m,maxm,Om,ExpZ,CenterAB,CenterZA,DY0,DY1,D2Y0,D2Y1) &
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+ CenterAB(1,xyz)* &
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HRR3e(AngMomBra,b1m,maxm,Om,ExpZ,CenterAB,CenterZA,DY0,DY1,D2Y0,D2Y1)
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!------------------------------------------------------------------------
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! 2nd horizontal recurrence relation (2 terms): <a1a2a3|b1b2+0>
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!------------------------------------------------------------------------
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elseif(TotAngMomKet(3) == 0) then
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do i=1,3
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do j=1,3
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a2p(i,j) = AngMomBra(i,j)
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b2m(i,j) = AngMomKet(i,j)
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enddo
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enddo
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! Loop over cartesian directions
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xyz = 0
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if (AngMomKet(2,1) > 0) then
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xyz = 1
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elseif(AngMomKet(2,2) > 0) then
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xyz = 2
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elseif(AngMomKet(2,3) > 0) then
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xyz = 3
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else
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write(*,*) 'xyz = 0 in HRR3e!'
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endif
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! End loop over cartesian directions
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a2p(2,xyz) = a2p(2,xyz) + 1
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b2m(2,xyz) = b2m(2,xyz) - 1
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a1a2a3b1b2b3 = HRR3e(a2p,b2m,maxm,Om,ExpZ,CenterAB,CenterZA,DY0,DY1,D2Y0,D2Y1) &
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+ CenterAB(2,xyz)* &
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HRR3e(AngMomBra,b2m,maxm,Om,ExpZ,CenterAB,CenterZA,DY0,DY1,D2Y0,D2Y1)
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!------------------------------------------------------------------------
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! 3rd horizontal recurrence relation (2 terms): <a1a2a3|b1b2b3+>
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!------------------------------------------------------------------------
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else
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do i=1,3
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do j=1,3
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a3p(i,j) = AngMomBra(i,j)
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b3m(i,j) = AngMomKet(i,j)
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enddo
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enddo
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! Loop over cartesian directions
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xyz = 0
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if (AngMomKet(3,1) > 0) then
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xyz = 1
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elseif(AngMomKet(3,2) > 0) then
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xyz = 2
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elseif(AngMomKet(3,3) > 0) then
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xyz = 3
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else
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write(*,*) 'xyz = 0 in HRR3e!'
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endif
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! End loop over cartesian directions
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a3p(3,xyz) = a3p(3,xyz) + 1
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b3m(3,xyz) = b3m(3,xyz) - 1
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a1a2a3b1b2b3 = HRR3e(a3p,b3m,maxm,Om,ExpZ,CenterAB,CenterZA,DY0,DY1,D2Y0,D2Y1) &
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+ CenterAB(3,xyz)* &
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HRR3e(AngMomBra,b3m,maxm,Om,ExpZ,CenterAB,CenterZA,DY0,DY1,D2Y0,D2Y1)
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endif
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end function HRR3e
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