As noted in Section 5.2, d - e-h ≡ 0 for any centrosymmetric system. To obtain a non-vanishing metric CT for systems with inversion symmetry, Ciofini et al. introduced alternative diagnostics that they call the "t index" and the "H index". The latter is essentially (σ elec + σ hole )/2, which provides a measure of the spread of the excitation, while the former is defined as t = D CT -H. We suggest replacing t with an alternative measure of essentially the same information, the charge-displacement distance 1