LASER SPECTROSCOPY OF DYSPROSIUM MONOFLUORIDE - LIGAND-FIELD ASSIGNMENTS OF STATES BELONGING TO THE 4F(9)6S(2), 4F(10)6S, AND 4F(9)6S6P SUPERCONFIGURATIONS

The techniques of selectively detected fluorescence excitation and dis persed fluorescence spectroscopy have been used to characterize two [1 9.3]8.5 and [20.3]8.5 electronic states of DyF in the region of simila r to 2.5 eV and five electronic states with T-0 < 6500 cm(-1). Superco nfigurational assignments of the observed low-lying states have been m ade on the basis of vibrational frequencies. The X(1)7.5 ground state, with Delta G(1/2) approximate to 605 cm(-1), is assigned to the Dy+ 4 f(9)6s(2) superconfiguration, whereas four states, (1)8.5, (2)7.5, (3) 7.5, and (4)7.5, with Delta G(1/2) approximate to 508-544 cm(-1) are a ssigned to the Dy+ 4f(10)6s superconfiguration. The lowest 4f(10)6s (O hm = 8.5) state is found to lie 2431 cm(-1) above the 4f(9)6s(2) X(1)7 .5 ground state, thus establishing the linkage between the 4f(9)6s(2) and 4f(10)6s superconfigurations. The upper states in the region of si milar to 2.5 eV ([19.3]8.5 and [20.3]8.5) are assigned to the Dy+ 4f(9 )6s6p superconfiguration on the basis of computed ligand field monopol e B-0(0)(nl, nl) orbital destabilization energies. The observed electr onic states are discussed in relation to predictions of the ligand fie ld theoretical model. (C) 1996 Academic Press, Inc.