8. xc#

8.1. lda_slater_x#

Slater exchange functional (spin-paired).

Python

Julia

1f = -3 / 4 * (3 / (2 * np.pi))**(2 / 3)
2rs = (3 / (4 * np.pi * n))**(1 / 3)
3
4ex = f / rs
5vx = 4 / 3 * ex
6return ex, vx
1f = -3.0 / 4.0 * (3.0 / (2.0 * pi))^(2.0 / 3.0)
2rs = (3.0 ./ (4.0 .* pi .* n)) .^ (1.0 / 3.0)
3
4ex = f ./ rs
5vx = 4.0 ./ 3.0 .* ex
6return ex, vx

8.2. lda_chachiyo_c#

Chachiyo parametrization of the correlation functional (spin-paired).

Python

Julia

1a = -0.01554535  # (np.log(2) - 1) / (2 * np.pi**2)
2b = 20.4562557
3
4rs = (3 / (4 * np.pi * n))**(1 / 3)
5
6ec = a * np.log(1 + b / rs + b / rs**2)
7vc = ec + a * b * (2 + rs) / (3 * (b + b * rs + rs**2))
8return ec, vc
1a = -0.01554535  # (log(2.0) - 1.0) / (2.0 * pi^2.0)
2b = 20.4562557
3
4rs = (3.0 ./ (4.0 .* pi .* n)) .^ (1.0 / 3.0)
5
6ec = a .* log.(1.0 .+ b ./ rs .+ b ./ rs .^ 2.0)
7vc = ec .+ a .* b .* (2.0 .+ rs) ./ (3.0 .* (b .+ b .* rs .+ rs .^ 2.0))
8return ec, vc