Analysis of hyperfine structure in the 0-0 band of the [17.6]2.5-X2.5 transition of iridium monoxide, IrO

摘要

Laser induced fluorescence spectra of the [17.6]2.5-X2.5 0-0 band of iridium monoxide, IrO, have been obtained at high resolution (<40 MHz). The hyperfine structure due to ~(193)Ir (I = 3/2) and ~(191)Ir (I = 3/2) is well resolved enabling determination of magnetic (h_(5/2)) and nuclear electric quadrupole (eQq0) hyperfine parameters for the [17.6]2.5 (v = 0) and X2.5 (v = 0) states. The dominant configuration of the ground state is determined by comparing the observed molecular hyperfine parameters with values calculated for several possible ground state configurations using atomic hyperfine parameters. A perturbation calculation suggests that the X2.5 state results from the mixing of the Ω = 5/2 component of the predicted ground ~4Δ_i state with the Ω = 5/2 components of two low-lying excited ~2Δ_i states.