Laser spectroscopy of dysprosium monoxide: Observation and analysis of several low-lying electronic states

Abstract

Single-frequency, tunable dye lasers have been used to excite several transitions in the DyO molecule. High-resolution wavelength selected excitation and resolved fluorescence spectroscopy have been used to study details of the electronic, vibrational, and rotational structure. Isotope structure was resolved and used as an aid in analysis. Five low-lying and three higher lying states were observed. The energies and Ω assignments of the states have been determined together with rotational constants and some vibrational frequencies. The low-lying states, including the Ω = 8 ground state, are shown, using ligand field theory, to result from ionically bonded Dy 2+O 2− in which the Dy 2+ configuration is 4f 9( 6H)6s . The energy level pattern is compared with and found to be in good agreement with detailed ligand field theory calculations. This comparison is used to assign free atomic ion quantum numbers to each low-lying state.