Vibrationally resolved Si 2p photoabsorption spectrum of SiF4

A high-resolution study of the Si 2p photoabsorption spectrum of gas-phase SiF4 is reported. In the excitation region of the Rydberg orbitals, vibrational substates from symmetric stretching vibrational modes were resolved, which were described on the basis of a Franck-Condon analysis resulting in vibrational energies and equilibrium interatomic distances of the core-excited molecule. The natural lifetime width of the Si 2p core excitation amounts to 85 meV, a value that is substantially larger than the theoretically predicted one.