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qp2/src/utils/cgtos_one_e.irp.f

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2023-03-04 17:49:48 +01:00
! ---
complex*16 function overlap_cgaussian_x(A_center, B_center, alpha, beta, power_A, power_B, dim)
BEGIN_DOC
!
! \int_{-infty}^{+infty} (x-A_x)^ax (x-B_x)^bx exp(-alpha (x-A_x)^2) exp(- beta(x-B_X)^2) dx
! with complex arguments
!
END_DOC
implicit none
include 'constants.include.F'
integer, intent(in) :: dim, power_A, power_B
complex*16, intent(in) :: A_center, B_center, alpha, beta
integer :: i, iorder_p
double precision :: fact_p_mod
complex*16 :: P_new(0:max_dim), P_center, fact_p, p, inv_sq_p
complex*16 :: Fc_integral
call give_explicit_cpoly_and_cgaussian_x( P_new, P_center, p, fact_p, iorder_p &
, alpha, beta, power_A, power_B, A_center, B_center, dim)
fact_p_mod = dsqrt(real(fact_p)*real(fact_p) + aimag(fact_p)*aimag(fact_p))
if(fact_p_mod .lt. 1.d-14) then
overlap_cgaussian_x = (0.d0, 0.d0)
return
endif
inv_sq_p = (1.d0, 0.d0) / zsqrt(p)
overlap_cgaussian_x = (0.d0, 0.d0)
do i = 0, iorder_p
overlap_cgaussian_x += P_new(i) * Fc_integral(i, inv_sq_p)
enddo
overlap_cgaussian_x *= fact_p
end function overlap_cgaussian_x
! ---
subroutine overlap_cgaussian_xyz( A_center, B_center, alpha, beta, power_A, power_B &
, overlap_x, overlap_y, overlap_z, overlap, dim )
BEGIN_DOC
!
! S_x = \int (x-A_x)^{a_x} exp(-\alpha(x-A_x)^2) (x-B_x)^{b_x} exp(-beta(x-B_x)^2) dx
! S = S_x S_y S_z
! for complex arguments
!
END_DOC
implicit none
include 'constants.include.F'
integer, intent(in) :: dim, power_A(3), power_B(3)
complex*16, intent(in) :: A_center(3), B_center(3), alpha, beta
complex*16, intent(out) :: overlap_x, overlap_y, overlap_z, overlap
integer :: i, nmax, iorder_p(3)
double precision :: fact_p_mod
complex*16 :: P_new(0:max_dim,3), P_center(3), fact_p, p, inv_sq_p
complex*16 :: F_integral_tab(0:max_dim)
complex*16 :: Fc_integral
call give_explicit_cpoly_and_cgaussian(P_new, P_center, p, fact_p, iorder_p, alpha, beta, power_A, power_B, A_center, B_center, dim)
fact_p_mod = dsqrt(real(fact_p)*real(fact_p) + aimag(fact_p)*aimag(fact_p))
if(fact_p_mod .lt. 1.d-14) then
overlap_x = (1.d-10, 0.d0)
overlap_y = (1.d-10, 0.d0)
overlap_z = (1.d-10, 0.d0)
overlap = (1.d-10, 0.d0)
return
endif
nmax = maxval(iorder_p)
inv_sq_p = (1.d0, 0.d0) / zsqrt(p)
do i = 0, nmax
F_integral_tab(i) = Fc_integral(i, inv_sq_p)
enddo
overlap_x = P_new(0,1) * F_integral_tab(0)
overlap_y = P_new(0,2) * F_integral_tab(0)
overlap_z = P_new(0,3) * F_integral_tab(0)
do i = 1, iorder_p(1)
overlap_x = overlap_x + P_new(i,1) * F_integral_tab(i)
enddo
call cgaussian_product_x(alpha, A_center(1), beta, B_center(1), fact_p, p, P_center(1))
overlap_x *= fact_p
do i = 1, iorder_p(2)
overlap_y = overlap_y + P_new(i,2) * F_integral_tab(i)
enddo
call cgaussian_product_x(alpha, A_center(2), beta, B_center(2), fact_p, p, P_center(2))
overlap_y *= fact_p
do i = 1, iorder_p(3)
overlap_z = overlap_z + P_new(i,3) * F_integral_tab(i)
enddo
call cgaussian_product_x(alpha, A_center(3), beta, B_center(3), fact_p, p, P_center(3))
overlap_z *= fact_p
overlap = overlap_x * overlap_y * overlap_z
end subroutine overlap_cgaussian_xyz
! ---