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qp2/src/dft_utils_func/mu_of_r_dft.irp.f
2021-11-09 15:48:49 +01:00

38 lines
990 B
Fortran

double precision function mu_rs_c(rho)
implicit none
double precision, intent(in) :: rho
include 'constants.include.F'
double precision :: cst_rs,alpha_rs,rs
cst_rs = (4.d0 * dacos(-1.d0)/3.d0)**(-1.d0/3.d0)
alpha_rs = 2.d0 * dsqrt((9.d0 * dacos(-1.d0)/4.d0)**(-1.d0/3.d0)) / sqpi
rs = cst_rs * rho**(-1.d0/3.d0)
mu_rs_c = alpha_rs/dsqrt(rs)
end
double precision function mu_grad_rho_func(r)
implicit none
double precision , intent(in) :: r(3)
integer :: m
double precision :: rho, dm_a, dm_b, grad_dm_a(3), grad_dm_b(3)
double precision :: eta, grad_rho(3), grad_sqr
eta = mu_erf
call density_and_grad_alpha_beta(r,dm_a,dm_b, grad_dm_a, grad_dm_b)
rho = dm_a + dm_b
do m = 1,3
grad_rho(m) = grad_dm_a(m) + grad_dm_b(m)
enddo
grad_sqr=0.d0
do m = 1,3
grad_sqr=grad_sqr+grad_rho(m)*grad_rho(m)
enddo
grad_sqr = dsqrt(grad_sqr)
if (rho<1.d-12) then
mu_grad_rho_func = 1.d-10
else
mu_grad_rho_func = eta * grad_sqr / rho
endif
end