The [Dtilde] 2 A 1-[Ctilde] 2 T 2 emission band system of SiF+4: Jahn-Teller distortion in the [Ctilde] 2 T 2 state

The [Dtilde] 2 A 1-[Ctilde] 2 T 2 emission spectrum of SiF+ 4 is observed at a low rotational temperature in a crossed molecular beam/electron beam apparatus. The narrow rotational envelope of the bands confirms the assignment of the emitter as the parent molecular ion of SiF4. The spectrum is analysed, and the results compare excellently with photoelectron data for SiF4. Spin-orbit splitting and Jahn-Teller distortion are observed in the [Ctilde] 2 T 2 state, with both v 2(e) and v 4(t 2) being Jahn-Teller active vibrations.