Comment on the Extended Hückel method applied to transition metal complexes

It is indicated that the effects of neglecting 1. the inter-atomic electrostatic field effects (M_i) and 2. the correction required to compensate the off-diagonal elements for the constant potential –Z implicitly included by approximating the diagonal elements as VSIE's largely cancel. To the extent that this cancellation holds, previous EH calculations may be rationalised in this regard.