Jahn--Teller effect in the lowest charge transfer state of UF6

The neat and mixed crystal emission spectra of UF6 are analyzed. It is found that long uniquantal progressions appear in the ν5 (t/sub 2g/) vibration built on the origin, ν6 (t/sub 2u/), and n1ν1 (a/sub 1g/). The maximum intensity in all these series falls around n5=2. These data are interpreted as being indicative of a substantial molecular Jahn--Teller interaction in the excited charge transfer state. Using a modified Franck--Condon analysis for a three-dimensional vibrational space, it is found that D5 approx.2.02 and that the excited state is distorted along each of three ν5 coordinates by roughly 0.09 A