Measurement of the A 3π1u←X 1Σ+g continuum absorptivity in Br2

Of the numerous attempts to decompose the visible absorption continuum of Br2 into its three components,1π1u,B3π1u →X 1𝒥+g, most have neglected the A←X continuum. Although the intensity of the absorption continuum underlying the B←X lines can in principle be measured, extreme spectral resolution is required in order to separate the bound–bound spectrum from the bound free. For the present experiment, a simpler approach was taken using a tunable dye laser, the output of which was 3.5 W at 514 nm.