18.1.36 THGFC:

D. J. Tozer, N. C. Handy and W. H. Green, Chem. Phys. Lett. 273, 183 (1997)

Density and gradient dependent first row exchange-correlation functional for closed shell systems. Total energies are improved by adding $DN$, where $N$ is the number of electrons and $D=0.1863$.

$$K= \sum _{i=1}^{n}\omega_{{i}}R_{{i}}X_{{i}} ,$$ (200)

where

$$n=12 ,$$ (201)

$$R_{{i}}=\rho_{\alpha}^{t_{{i}}}+\rho_{\beta} ^{t_{{i}}} ,$$ (202)

$$X_{{i}}={\frac {\sigma_{\alpha \alpha}^{v_{ {i}/2}}+\sigma_{\beta \beta}^{v_{{i}/2}}}{{2\rho}^{4v_{{i}}/ 3 }}} ,$$ (203)

$$t = [7/6,4/3,3/2,5/3,4/3,3/2,5/3,{\frac {11}{6}},3/2,5/3,{\frac {11}{6}},2] ,$$ (204)

$$v = [0,0,0,0,1,1,1,1,2,2,2,2]$$ (205)

and

$$\omega = [- 0.864448, 0.565130,- 1.27306, 0.309681,- 0.287658, 0.588767,$$

$$- 0.252700, 0.0223563, 0.0140131,- 0.0826608, 0.0556080,$$

$$- 0.00936227] .$$ (206)