Electronic transitions of iridium monophosphide

Abstract Laser induced fluorescence spectrum of IrP in the near infrared spectral region between 720 and 820 nm has been recorded and analyzed. Six vibrational bands with resolved rotational structure for both 191 IrP and 193 IrP were analyzed, they have been grouped into three new electronic transitions: the [13.6] Ω  = 2 −  a 3 Π 2 , the [12.3] 1 Π 1 –X 1 Σ + , and the [12.7] 1 Π 1 –X 1 Σ + transitions. Ab initio calculation results were used to aid the assignment of the observed transitions. A new triplet state has been observed for the first time. The observed electronic states of IrP are compared with those of the isovalent IrN molecule.