Absorption spectrum of Ba2

Abstract

Three groups of bands, within approximate wavelength ranges 5670–5708, 5803–5820 and 5830–5850 Å, have been photographed in absorption. We believe the absorbing molecule to be Ba₂. Two groups may be fitted as 0–0 and 1–0 sequences to give the vibrational constants (in cm^–1): ω^″_e= 80.125 ± 0.031, ω^″_ex^″_e= 0.1605 ± 0.0047 and ω^′_e= 89.75 ± 0.06, ω^′_ex^′_e= 0.176 ± 0.009. The third group may be two 0–0 sequences of a multiplet transition. Several bands have striking and unusual features.