P. M. Sheridan

High-resolution investigation of the excited electronic states of CaSH and SrSH by laser excitation spectroscopy

A laser ablation/pulsed molecular jet system has been used to record high-resolution laser excitation spectra of the 2 A′– 2 A′ transition of CaSH and the 2 A′– 2 A′, 2 A″– 2 A′, and 2 A′– 2 A′ transitions of SrSH. The rotationally-resolved data were analysed using an asymmetric top Hamiltonian (A-reduction) to determine rotational and fine structure parameters. A combined fit of all the newly measured and the previously recorded spectroscopic data for both CaSH and SrSH was performed. In the excited states observed in this study, both species were found to have a bent geometry. The spin-rotation parameters were analysed in terms of the pure precession and unique perturber approximations. In the excited electronic states of SrSH, the large spin-rotation interaction was found to cause perturbations between the Ka  = 0 and 1 levels within each state. In the 2 A′ and 2 A″ states of both species, the metal-sulfur bond length was found to decrease relative to the ground state, which is consistent with previous...

High-resolution laser excitation spectroscopy of the ÃE2-X̃A12 transition of SrCH3

High-resolution laser excitation spectroscopy has been used to record the AE2-XA12 electronic transition of SrCH3 in a laser ablation/molecular jet source. Transitions arising from the K′=1←K″=0, K′=0←K″=1, and K′=2←K″=1 subbands have been observed and assigned. The data were modeled with E2 and A12 symmetric top Hamiltonian matrices in a Hund’s case (a) basis, using a least squares fitting program. Rotational and fine structure parameters for the AE2 state were determined. A comparison of the spin-orbit energy separation in the AE2 state to other strontium containing free radicals showed that the Jahn-Teller effect is negligible. The spin-rotation constants for the AE2 state were calculated using the pure precession model and were found to be in good agreement with the experimentally determined parameters. These calculations suggest that the AE2 state of SrCH3 is not entirely of p orbital character. The rotational constants were used to estimate the structural parameters of SrCH3 in the AE2 state....

High-resolution investigation of the excited electronic states of CaSH and SrSH by laser excitation spectroscopy – ARTICLE WITHDRAWN

WITHDRAWN TO APPEAR IN SPECIAL ISSUE IN 2007

High-resolution laser excitation spectroscopy of the A2E-X2A1 transition of SrCH3.

High-resolution laser excitation spectroscopy has been used to record the AE2-XA12 electronic transition of SrCH3 in a laser ablation/molecular jet source. Transitions arising from the K′=1←K″=0, K′=0←K″=1, and K′=2←K″=1 subbands have been observed and assigned. The data were modeled with E2 and A12 symmetric top Hamiltonian matrices in a Hund’s case (a) basis, using a least squares fitting program. Rotational and fine structure parameters for the AE2 state were determined. A comparison of the spin-orbit energy separation in the AE2 state to other strontium containing free radicals showed that the Jahn-Teller effect is negligible. The spin-rotation constants for the AE2 state were calculated using the pure precession model and were found to be in good agreement with the experimentally determined parameters. These calculations suggest that the AE2 state of SrCH3 is not entirely of p orbital character. The rotational constants were used to estimate the structural parameters of SrCH3 in the AE2 state....

High-resolution laser excitation spectroscopy of the ÃE2-X̃A12 transition of SrCH3

High-resolution laser excitation spectroscopy has been used to record the AE2-XA12 electronic transition of SrCH3 in a laser ablation/molecular jet source. Transitions arising from the K′=1←K″=0, K′=0←K″=1, and K′=2←K″=1 subbands have been observed and assigned. The data were modeled with E2 and A12 symmetric top Hamiltonian matrices in a Hund’s case (a) basis, using a least squares fitting program. Rotational and fine structure parameters for the AE2 state were determined. A comparison of the spin-orbit energy separation in the AE2 state to other strontium containing free radicals showed that the Jahn-Teller effect is negligible. The spin-rotation constants for the AE2 state were calculated using the pure precession model and were found to be in good agreement with the experimentally determined parameters. These calculations suggest that the AE2 state of SrCH3 is not entirely of p orbital character. The rotational constants were used to estimate the structural parameters of SrCH3 in the AE2 state....