B86b †
\[ F_x(s)=1+\frac{\mu s^2}{(1+\mu s^2/\kappa)^{4/5}} \]
Method | \( \mu \) | \( \kappa \) | Reference |
B86b | 0.2449 | 0.5757 | A. D. Becke, J. Chem. Phys. 85, 7184 (1986) |
optB86b | 0.1234 (=10/81) | 1 | J. Klimes et al., Phys. Rev. B 83, 195131 (2011) |
B86R | 0.1234 (=10/81) | 0.7114 | I. Hamada, Phys. Rev. B 89, 121103(R) (2014) |
PW86 †
\[ F_x(s)=(1+15as^2+bs^4+cs^6)^{1/15} \]
Method | \( a \) | \( b \) | \( c \) | Reference |
PW86 | 0.0864 | 14 | 0.2 | J. P. Perdew and Y. Wang, Phys. Rev. B 33, 8800(R) (1986) |
PW86R | 0.1234 (=10/81) | 17.33 | 0.163 | E. D. Murray et al., J. Chem. Theory Comput. 10, 2754 (2009) |
B88 †
\[ F_x(s)=1+\frac{\mu s^2}{1+\frac{9}{4\pi}\mu s\,{\rm sinh}^{-1}(\lambda s)} \]
Method | \( \mu \) | \( \lambda \) | Reference |
B88 | 0.2743 | \( 2(6\pi^2)^{1/3} \) | A. D. Becke, Phys. Rev. A 38, 3098 (1988) |
optB88 | 0.22 | \( 1.2\times(9/2)(6/\pi)^{1/3} \) | J. Klimes et al., J. Phys. Cond. Mat. 22, 022201 (2010) |
PBE †
\[ F_x(s)=1+\kappa-\frac{\kappa}{1+\mu s^2/\kappa} \]
Method | \( \mu \) | \( \kappa \) | Reference |
| 0.235 | 0.967 | A. D. Becke, J. Chem. Phys. 84, 4524 (1986) |
PBE | 0.21951 | 0.804 | J. P. Perdew et al., Phys. Rev. Lett. 77, 3865 (1996) |
optPBE | 0.175519 | 1.04804 | J. Klimes et al., J. Phys. Cond. Mat. 22, 022201 (2010) |