Hyperfine structure and Stark effect in the [18.0] 4 − X3Φ4 transition of iridium hydride, IrH and [18.2] 4 − X3Φ4 transition of iridium deuteride, IrD

Abstract

High resolution spectra of IrH and IrD, with full width at half maximum (FWHM) of ~0.001 cm-1 , have shown well resolved hyperfine structure due to the nuclear spin, I = 3/2, of 193 Ir and 191 Ir. Analysis of the hyperfine structure in the [18.2]4-X 3 Φ4 transition of 193 IrD and 191 IrD yielded well defined magnetic and quadrupole Ir hyperfine parameters which showed that the ground X 3 Φ4 state originates predominantly from the two open-shell Ir(5dπ 3 5dδ 3) configuration with a significant contribution from the four open-shell Ir(5dσ5dπ 3 5dδ 3 6sσ) configuration. Examination of the Stark effect in the [18.0]4-X 3 Φ4 transition of 193 IrH yielded electric dipole moments of 1.23(1) D and 0.76(1) D for the ground and excited states, respectively. The hyperfine constants and the dipole moment of the ground state are seen to follow the trend shown by the isovalent molecules, CoF, CoH and IrF.