. 2014 Mar 12;10(4):1518–1537. doi: 10.1021/ct401002w

Table 1. Overview of Electronic Parameters (in Atomic Units if not Unitless)^a.

parameter	S	P
l_max	2	2
n_max	2	2
α₀	0.50	0.50
α₁	1.19	1.17
α₂	2.83	2.74
α₃	6.73	6.41
α₄	16.00	15.00
r^wf	3.8	3.6
r^wfd	4.4	4.4
r^dens	9.0	9.0
ε_s	–0.63 000 872	–0.51 063 909
ε_p	–0.25 802 653	–0.20 276 532
ε_d	0.32 140 766	0.52 019 087
E^spin	–0.03 121 074	–0.06 868 820
U	0.3288	0.2894
U^d	–0.11	–0.14

As described in the text, U, E^spin, ε_s,p, n_max, and α_i are in line with the standard choices of DFTB parametrization and not subject to optimizations. By contrast, r^wf, r^wfd, r^dens, ε_d, and U^d are adjusted based on properties of molecules in the fitting set.

Table 1. Overview of Electronic Parameters (in Atomic Units if not Unitless)a.

Table 1. Overview of Electronic Parameters (in Atomic Units if not Unitless)^a.