Effect of isotope shifts in the blue–green band spectrum of the lead dimer

Abstract

The absorption spectrum of gaseous Pb2 has been investigated in the blue – green spectral region. Owing to the overlap between the six dominating isotopic Pb2 molecules formed by natural lead – in combination with the very dense structure of the [Formula: see text] transition – it is impossible to rotationally resolve the Doppler limited spectrum. Still, regions of rotational structure were resolved. These were explained by interference effects between the absorption spectra of the individual isotopic species. The regions of resolved rotational structure form a pattern similar to a moiré pattern. The information gained is used together with laser induced fluorescence data in a reanalysis of the F and X states. The following main molecular constants for the 208Pb2 molecule have been derived (cm−1):[Formula: see text]