Comparison of theoretical and experimental data shown in Table reveals that for X = Br, i.e., for the [(bipy)CuBr] + and [(bipy)AuBr] + complexes, both transitions are experimentally observed and the calculations are in a very good agreement with the experimental values (to within 2-20 nm). For [(bipy)CuCl] + , the predicted calc (b2) = 455 nm seems to correspond to the experimental band appearing at the end of the short-wave-length of the experimental spectra (~ 450 nm) whereas the predicted calc (a1) at 684 nm seems to be hidden in noise on the other end of the experimental spectra (Figure ). For [(bipy)AuCl] + , the predicted calc (b2) = 416 nm in the C2v geometry and calc (a") = 433 nm in the Cs minimum (see discussion below) is clearly outside the experimental window (min ~ 450 nm). This explains the missing b2 band in the spectrum of [(bipy)AuCl] + (Figure ).