1(* 2 Copyright (C) 2017 M.A.L. Marques 3 2019 Susi Lehtola 4 5 This Source Code Form is subject to the terms of the Mozilla Public 6 License, v. 2.0. If a copy of the MPL was not distributed with this 7 file, You can obtain one at http://mozilla.org/MPL/2.0/. 8*) 9 10(* type: gga_exc *) 11(* prefix: 12 gga_c_pbe_vwn_params *params; 13 14 assert(p->params != NULL); 15 params = (gga_c_pbe_vwn_params * )(p->params); 16*) 17 18$include "lda_c_vwn.mpl" 19$ifdef gga_c_pbe_params 20params_a_beta := 0.06672455060314922: 21params_a_gamma := (1 - log(2))/Pi^2: 22params_a_BB := 1: 23$endif 24 25mgamma := params_a_gamma: 26mbeta := (rs, t) -> params_a_beta: 27BB := params_a_BB: 28 29tp := (rs, z, xt) -> tt(rs, z, xt): 30 31(* Equation (8) *) 32A := (rs, z, t) -> 33 mbeta(rs, t)/(mgamma*(exp(-f_vwn(rs, z)/(mgamma*mphi(z)^3)) - 1)): 34 35(* Equation (7) *) 36f1 := (rs, z, t) -> t^2 + BB*A(rs, z, t)*t^4: 37f2 := (rs, z, t) -> mbeta(rs, t)*f1(rs, z, t)/(mgamma*(1 + A(rs, z, t)*f1(rs, z, t))): 38 39fH := (rs, z, t) -> mgamma*mphi(z)^3*log(1 + f2(rs, z, t)): 40 41f_pbe := (rs, z, xt, xs0, xs1) -> 42 f_vwn(rs, z) + fH(rs, z, tp(rs, z, xt)): 43 44f := (rs, z, xt, xs0, xs1) -> f_pbe(rs, z, xt, xs0, xs1): 45 46