Laser spectroscopy of the A[16.4]8.5-X7.5, A[16.4]8.5-Y[0.15]8.5, and A[16.4]8.5-Z[0.85]7.5 transitions of dysprosium monochloride

Laser-induced fluorescence spectra have been obtained at low resolution using a laser ablation source and pulsed dye laser, and at high resolution using a Broida oven and cw ring dye laser. Dispersed fluorescence spectra from two different excited states, A[16.4]8.5 and B[15.4]Ω (unknown Ω) (the states are labelled [10−3T0]Ω according to their energy and Ω assignment) showed transitions to the same four low lying electronic states, X7.5, Y[0.15]8.5, Z[0.85]7.5, and an unassigned state at 970 cm−1. High resolution excitation spectra of the A-X 0-0, A-Y 0-0 and 0-1, and A-Z 0-0 and 0-1 transitions were obtained and a global fit to all the data yielded rotational constants for both 162Dy35Cl and 164Dy35Cl. From the band origins, vibrational frequencies of 291 and 284 cm−1 were obtained for the Y[0.15]8.5 and Z[0.85]7.5 states, respectively, suggesting that these two states originate from the Dy+(4f106s)Cl− configuration. The 162Dy-164Dy and 35Cl-37Cl isotope effects were studied and both indicated a ground state, X7.5, vibrational frequency of ∼230 cm−1 which was reinforced by the observation, in dispersed fluorescence from the B[15.4] state, of a weak transition to a state 233 cm−1 above the ground state. The observed electronic states and their configurational origin are discussed in terms of ligand field theory predictions.