Hyperfine Interactions and Electric Dipole Moments in the [16.0]1.5(v = 6), [16.0]3.5(v = 7), and X²Δ_5/2 States of Iridium Monosilicide, IrSi

Abstract

The (6,0)[16.0]1.5-X(2)Δ(5/2) and (7,0)[16.0]3.5-X(2)Δ(5/2) bands of IrSi have been recorded using high-resolution laser-induced fluorescence spectroscopy. The field-free spectra of the (191)IrSi and (193)IrSi isotopologues were modeled to generate a set of fine, magnetic hyperfine, and nuclear quadrupole hyperfine parameters for the X(2)Δ(5/2)(v = 0), [16.0]1.5(v = 6), and [16.0]3.5 (v = 7) states. The observed optical Stark shifts for the (193)IrSi and (191)IrSi isotopologues were analyzed to produce the permanent electric dipole moments, μ(el), of -0.414(6) D and 0.782(6) D for the X(2)Δ(5/2) and [16.0]1.5 (v = 6) states, respectively. Properties of the X(2)Δ(5/2) state computed using relativistic coupled-cluster methods clearly indicate that electron correlation plays an essential role. Specifically, inclusion of correlation changes the sign of the dipole moment and is essential for achieving good accuracy for the nuclear quadrupole coupling parameter eQq0.

Analytic energy derivatives in relativistic quantum chemistry

“…[206] Initial applications of SFX2C-1e energy derivatives in the calculation of the properties of heavy-element compounds have turned out promising. [207][208][209][210][211][212][213][214][215] A more detailed discussion of analytic SFX2C-1e energy derivatives is presented in the following. We also refer the reader to a recent review on this topic by Filatov et al [216] Finally, we mention that the full X2C formulation, which includes SO interactions, has been used for DFT calculation of electrical properties [181] and NMR chemical shieldings.…”