Calculated equilibrium coordinates for the 3 2 A² state in Table defined rotational constants of A'=0.5784, B'=0.1618 and C'=0.1264 cm -1 . The electronic state symmetries dictate a c-type transition which produced a simulation that was qualitatively different from the observed contour. However, a reasonably good correspondence with the observed band contour (cf. Fig. ) was obtained by adjusting the upper state geometry to RThO=1.85 Å, RThF=2.10 Å, q=116.5º, which yielded the rotational constants A'=0.540, B'=0.1655, and C'=0.1266 cm -1 . The details of the band contour were sensitive to small changes in the geometry, and the constants used in the simulation of Fig. were certainly not unique. The purpose of the simulation was to show that the band contour was consistent with only a small change in the geometry on electronic excitation.