The rotational structure of the laser-excited fluorescence of yttrium monoi
odide, recorded on a Fourier transform spectrometer, was analyzed, enabling
the characterization of two excited states at T-c similar to 20 690 and si
milar to 24 100 cm(-1). Observation of the ground state X(1)Sigma(+) is ext
ended up to v = 15. A scheme for the electronic structure is proposed, invo
lving the X(1)Sigma(+), B(1)Pi, D(1)Pi, Ohm 1 and possibly A((1)Delta) stat
es. (C) 1999 Academic Press.