mirror of https://github.com/pfloos/quack
44 lines
862 B
Fortran
44 lines
862 B
Fortran
subroutine CalcOmYuk(maxm,ExpG,ExpY,fG,NormYSq,Om)
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! Compute the 0^m for the screened Coulomb operator: (00|f12/r12|00)^m
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implicit none
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! Input variables
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integer,intent(in) :: maxm
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double precision,intent(in) :: ExpG,ExpY,fG,NormYSq
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! Local variables
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integer :: m,k
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double precision :: pi,t,dbinom
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double precision,allocatable :: Fm(:)
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! Output variables
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double precision,intent(inout):: Om(0:maxm)
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allocate(Fm(0:maxm))
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pi = 4d0*atan(1d0)
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! Campute generalized Boys functions
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t = (ExpY - fG)*NormYSq
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call CalcBoysF(maxm,t,Fm)
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! Compute (00|00)^m
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do m=0,maxm
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Om(m) = 0d0
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do k=0,m
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Om(m) = Om(m) + dbinom(m,k)*(ExpY/ExpG)**k*Fm(k)
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enddo
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Om(m) = (2d0/sqrt(pi))*sqrt(ExpY)*(fG/ExpG)*exp(-fG*NormYSq)*Om(m)
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enddo
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deallocate(Fm)
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end subroutine CalcOmYuk
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