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

Abstract

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 −3 T 0] 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 162Dy 35Cl and 164Dy 35Cl. 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 +(4 f 106s)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.