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quantum_package/plugins/DFT_Utils/integration_radial.irp.f
2016-07-16 16:09:50 +02:00

110 lines
3.6 KiB
Fortran

BEGIN_PROVIDER [ double precision, integral_density_alpha_knowles_becke_per_atom, (nucl_num)]
&BEGIN_PROVIDER [ double precision, integral_density_beta_knowles_becke_per_atom, (nucl_num)]
implicit none
double precision :: accu
integer :: i,j,k,l
double precision :: x
double precision :: integrand(n_points_angular_grid), weights(n_points_angular_grid)
double precision :: f_average_angular_alpha,f_average_angular_beta
double precision :: derivative_knowles_function,knowles_function
! Run over all nuclei in order to perform the Voronoi partition
! according ot equation (6) of the paper of Becke (JCP, (88), 1988)
! Here the m index is referred to the w_m(r) weight functions of equation (22)
! Run over all points of integrations : there are
! n_points_radial_grid (i) * n_points_angular_grid (k)
do j = 1, nucl_num
integral_density_alpha_knowles_becke_per_atom(j) = 0.d0
integral_density_beta_knowles_becke_per_atom(j) = 0.d0
do i = 1, n_points_radial_grid-1
! Angular integration over the solid angle Omega for a FIXED angular coordinate "r"
f_average_angular_alpha = 0.d0
f_average_angular_beta = 0.d0
do k = 1, n_points_angular_grid
f_average_angular_alpha += weights_angular_points(k) * one_body_dm_mo_alpha_at_grid_points(k,i,j) * weight_functions_at_grid_points(k,i,j)
f_average_angular_beta += weights_angular_points(k) * one_body_dm_mo_beta_at_grid_points(k,i,j) * weight_functions_at_grid_points(k,i,j)
enddo
!
x = grid_points_radial(i) ! x value for the mapping of the [0, +\infty] to [0,1]
double precision :: contrib_integration
! print*,m_knowles
contrib_integration = derivative_knowles_function(alpha_knowles(int(nucl_charge(j))),m_knowles,x) &
*knowles_function(alpha_knowles(int(nucl_charge(j))),m_knowles,x)**2
integral_density_alpha_knowles_becke_per_atom(j) += contrib_integration *f_average_angular_alpha
integral_density_beta_knowles_becke_per_atom(j) += contrib_integration *f_average_angular_beta
enddo
integral_density_alpha_knowles_becke_per_atom(j) *= dr_radial_integral
integral_density_beta_knowles_becke_per_atom(j) *= dr_radial_integral
enddo
END_PROVIDER
double precision function knowles_function(alpha,m,x)
implicit none
BEGIN_DOC
! function proposed by Knowles (JCP, 104, 1996) for distributing the radial points :
! the Log "m" function ( equation (7) in the paper )
END_DOC
double precision, intent(in) :: alpha,x
integer, intent(in) :: m
knowles_function = -alpha * dlog(1.d0-x**m)
end
double precision function derivative_knowles_function(alpha,m,x)
implicit none
BEGIN_DOC
! derivative of the function proposed by Knowles (JCP, 104, 1996) for distributing the radial points
END_DOC
double precision, intent(in) :: alpha,x
integer, intent(in) :: m
derivative_knowles_function = alpha * dble(m) * x**(m-1) / (1.d0 - x**m)
end
BEGIN_PROVIDER [double precision, alpha_knowles, (100)]
implicit none
integer :: i
BEGIN_DOC
! recommended values for the alpha parameters according to the paper of Knowles (JCP, 104, 1996)
! as a function of the nuclear charge
END_DOC
! H-He
alpha_knowles(1) = 5.d0
alpha_knowles(2) = 5.d0
! Li-Be
alpha_knowles(3) = 7.d0
alpha_knowles(4) = 7.d0
! B-Ne
do i = 5, 10
alpha_knowles(i) = 5.d0
enddo
! Na-Mg
do i = 11, 12
alpha_knowles(i) = 7.d0
enddo
! Al-Ar
do i = 13, 18
alpha_knowles(i) = 5.d0
enddo
! K-Ca
do i = 19, 20
alpha_knowles(i) = 7.d0
enddo
! Sc-Zn
do i = 21, 30
alpha_knowles(i) = 5.d0
enddo
! Ga-Kr
do i = 31, 36
alpha_knowles(i) = 7.d0
enddo
END_PROVIDER