Laser spectroscopy of the [17.9]4 – X3Φ4 and [15.6]Ω – X3Φ4 transitions of iridium monochloride (IrCl)

Abstract

Laser Induced Fluorescence (LIF) spectra of two electronic transitions, [17.9]4 – X3Φ4 and [15.6]Ω – X3Φ4, of IrCl have been obtained in a laser-ablation molecular beam source, at low resolution using a pulsed dye laser, and at high resolution using a single mode ring dye laser. The 193Ir35Cl–193Ir37Cl isotope shifts of the band heads in the low resolution spectra established the vibrational assignment of the 0-0, 1-0, 2-0 and 0-1 bands of the [17.9]4 – X3Φ4 transition and the 0-0 and 1-0 bands of the [15.6]Ω – X3Φ4 transition. High resolution spectra (linewidth∼0.006cm−1 FWHM) were obtained for the 0-0, 1-0 and 2-0 bands of the more intense [17.9]4 – X3Φ4 transition. Rotational structure in the three bands of both 193Ir35Cl and 191Ir35Cl isotopologues was resolved and analyzed. The higher J rotational lines are observed to split into closely spaced doublets resulting from quadrupole hyperfine structure caused by the I=3/2 nuclear spin in 191Ir and 193Ir. Examination of the spectra shows that the doublet separation of ∼0.008cm−1 is similar to that observed in IrF (Linton et al., 2011) indicating that the quadrupole parameters, eQq0, are similar in IrF and IrCl.