Magnetic resonance-Raman optical activity of IrBr2−6

Abstract Magnetic optical activity in resonance Raman spectra of IrB 2− 6 are reported. Couplets are observed in all three Raman fundamentals (A 1g , E g and T 2g ) at 514.5 nm, but only in A 1g at 577.5 nm. These originate in transitions between Zeeman levels of the Kramers-degenerate ground state. From the absolute sign in the A 1g band, the isotropic g factor is confirmed to be negative.