Fluorescence from SF6 in highly excited vibrational states: An overview

Abstract

The spectroscopy of SF 6 , excited in its quasi-continuum by IR multiphoton absorption, has been recorded by IR fluorescence from ν = 700 to 1300 cm −1 with a highly sensitive device. The far resonance fluorescence exhibits structures directly connected to the intramolecular couplings. A model of couplings has been developed, the parameters of which are fixed by the experimental results. The strongest couplings (orders k = 3 and 4) have a density so low that they produce only a perturbative redistribution of the ν 3 mode. The dissipative redistribution is produced by the highest orders k ⩾5 and can be represented by a half-linewidth γ d ∼1.5 cm −1 for E vib ∼ 15,000 cm −1 . The onset of the SF 6 quasi-continuum is also predicted by the model, with characteristics in full agreement with published data.