High resolution spectra of IrH and IrD, with full width at half maximum (FWHM) of ∼0.001cm−1, have shown well resolved hyperfine structure due to the nuclear spin, I=3/2, of 193Ir and 191Ir. Analysis of the hyperfine structure in the [18.2] 4−X3Φ4 transition of 193IrD and 191IrD yielded well defined magnetic and quadrupole Ir hyperfine parameters which showed that the ground X3Φ4 state originates predominantly from the two open-shell Ir(5dπ35dδ3) configuration with a significant contribution from the four open-shell Ir(5dσ5dπ35dδ36sσ) configuration. Examination of the Stark effect in the [18.0] 4−X3Φ4 transition of 193IrH 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.

Laser induced fluorescence spectra of two electronic transitions, [17.6]2.5–X2.5 and [23.3]2.5–X2.5, of IrO have been obtained at high resolution by using a single mode ring dye laser to excite IrO molecules in a laser-ablation molecular beam source. The 191 IrO– 193 IrO isotope shifts in the rotational lines, observed at a linewidth of ∼0.006 cm −1 FWHM, established the vibrational assignment of the [23.3]2.5–X2.5 band as 1–0 and confirmed the previous 0–0 assignment of the [17.6]2.5–X2.5 band. The higher J rotational lines of both transitions are observed to split into closely spaced doublets resulting from quadrupole hyperfine structure caused by the I = 3/2 nuclear spin in 191 Ir and 193 Ir. Analysis of the spectra shows that the hyperfine structure is concentrated in the two excited states with quadrupole coupling constants, eQq 0 , of −0.0463(15) cm −1 and −0.0278(18) cm −1 for the [17.6]2.5 and [23.3]2.5 states respectively.

Laser-induced fluorescence spectra of iridium monohydride (IrH) and monodeuteride (IrD) have been obtained at medium resolution. Eight red-degraded bands for each isotopologue were observed. The bands are assigned as Ω′ = 4 − Ω″ = 4 transitions with the ground state common to all bands in each isotopologue. The data are consistent with the ground state being the lowest component of a 3Φi state. A global fit of all the rotationally resolved data yielded a set of rotation and distortion constants for each band. Ground state vibrational frequencies for IrH and IrD were determined to be 2216 and 1610 cm−1.

Author Institution: Physics Department and Centre for Laser, Atomic and Molecular Sciences, University of New Brunswick, Fredericton, NB, Canada E3B 5A3; Chemistry Department and Centre for Laser, Atomic and Molecular Sciences, University of New Brunswick, Fredericton, NB, Canada E3B 5A3; Department of Chemistry and Biochemistry, Arizona State University, Tempe,AZ 85287, USA.

Author Institution: Chemistry Department, and Centre for Lasers, and Atomic, and Molecular Sciences, University of New Brunswick, Fredericton, NB, E3B 5A3; Physics Department, and Centre for Lasers, and Atomic, and Molecular Sciences, University of New Brunswick, Fredericton, NB, E3B 5A3

Author Institution: Centre for Laser, Atomic, and Molecular Sciences and Physics Department, 8 Bailey Dr., University of New Brunswick, P.O. Box 4400, Fredericton, NB, Canada E3B 5A3; Centre for Laser, Atomic, and Molecular Sciences and Chemistry Department, 30 Dineen Dr., University of New Brunswick, P.O. Box 4400, Fredericton, NB, Canada E3B 5A3

The 000 bands of the A2E–X2A1 and B2A1–X2A1 electronic transitions of SrO12CH3 and the B2A1–X2A1 transition of SrO13CH3 have been recorded at high resolution using a laser ablation jet source. The optical–optical double resonance population depletion technique was used to facilitate the assignment of the spectra. Rotational levels with K=0, ±1 in the X2A1 and B2A1 states and K=0, 1 and 2 in the A2E state have all been characterised. A perturbation affecting the B2A1 state caused a reversal of the ordering of the spin-rotation components, F1 and F2, in the SrO12CH3 isotopologue. This required the introduction of a modified rotational constant Bmod, affecting only the K=1, F2 component of the B2A1 state, in order to model the SrO12CH3 data in a global fit of the A2E–X2A1 and B2A1–X2A1 transitions.

Author Institution: Centre for Laser, Atomic, and Molecular Sciences and Physics Department, 8 Bailey Dr., University of New Brunswick, P.O. Box 4400, Fredericton, NB, Canada E3B 5A3; Centre for Laser, Atomic, and Molecular Sciences and Chemistry Department, 30 Dineen Dr., University of New Brunswick, P.O. Box 4400, Fredericton, NB, Canada E3B 5A3

Laser induced fluorescence spectra of iridium monophosphide, IrP, have been obtained at low and high resolution in the blue region of the visible spectrum. Two electronic transitions were observed with origins near 459.6 and 471.9nm. Three vibronic bands in each of these transitions have been observed at high resolution allowing for full characterization of the states. A J-independent doubling of the rotational lines has been ascribed to nuclear electric quadrupole coupling in the ground state. Multireference configuration interaction (MRCI) calculations have been performed in order to confirm the nature of the ground state and aid in the assignment of the excited states. The two observed transitions have been assigned as the [21.7]1Σ+–X1Σ+ and the [21.2] 3Σ+–X1Σ+ electronic systems based on comparison with the theoretical calculations. The v+2 level of each of these electronic transitions was found to be heavily perturbed and a successful deperturbation analysis was performed allowing for a complete global fit of the data.

Author Institution: Centre for Laser, Atomic, and Molecular Sciences and Physics Department, 8 Bailey Dr., University of New Brunswick, P.O. Box 4400, Fredericton, NB, Canada E3B 5A3; Centre for Laser, Atomic, and Molecular Sciences and Chemistry Department, 30 Dineen Dr., University of New Brunswick, P.O. Box 4400, Fredericton, NB, Canada E3B 5A3

The 000 band of the A˜2Π-X˜2Σ+ transition of MgC4H has been recorded at high resolution using laser-induced fluorescence. The molecules were produced using an ablation source by the reaction of magnesium and ∼10% acetylene seeded in helium. The rotationally-resolved high-resolution data were fitted to obtain rotational and fine structure parameters for both states. The centrifugal distortion, upper state Λ-doubling and ground state spin-rotation splitting parameters were all found to be negligible and the reasons for this are investigated and discussed. The 301 band heads of the A˜2Π-X˜2Σ+ transition of MgC6H were obtained but the rotational structure was not resolved.

Laser-induced fluorescence spectra of iridium monofluoride (IrF) have been obtained at both low and high resolution. Two transitions have been observed; based on the rotational analysis of the high-resolution spectra, they have been assigned as A(3)Phi(i)-X-3 Phi(i) and B-3 Phi(i)-X-3 Phi(i). For the X (ground) and B states, only the lowest Omega = 4 components have been observed, while for the A state, the two lowest components, Omega = 4 and 3, were detected. A global fit to all of the high-resolution data (six bands of A-X and five of B-X) yielded a complete set of molecular constants for all three states of both (IrF)-Ir-191 and (IrF)-Ir-193. The v = 3 level of the A(3)Phi(4) state was found to be heavily perturbed and many extra lines belonging to the perturbing state were observed for each isotopologue. A deperturbation analysis showed that the perturber is an Omega = 5 state, and molecular parameters for this state were obtained.

Author Institution: Chemistry Department, and Centre for Lasers, and Atomic, and Molecular Sciences, University of New Brunswick, Fredericton, NB, E3B 6E2; Physics Department, and Centre for Lasers, and Atomic, and Molecular Sciences, University of New Brunswick, Fredericton, NB, E3B 5A3

Laser-induced fluorescence spectra of iridium monofluoride (IrF) have been obtained at both low and high resolution. Two transitions have been observed; based on the rotational analysis of the high-resolution spectra, they have been assigned as A3Φi-X3Φi and B3Φi-X3Φi. For the X (ground) and B states, only the lowest Ω = 4 components have been observed, while for the A state, the two lowest components, Ω = 4 and 3, were detected. A global fit to all of the high-resolution data (six bands of A-X and five of B-X) yielded a complete set of molecular constants for all three states of both 191IrF and 193IrF. The v = 3 level of the A3Φ4 state was found to be heavily perturbed and many extra lines belonging to the perturbing state were observed for each isotopologue. A deperturbation analysis showed that the perturber is an Ω = 5 state, and molecular parameters for this state were obtained.