Near-infrared emission bands were observed near 6200 and 5700 cm(-1) when water vapor (H2O, D2O) was added to the reaction of bismuth vapor (Bi-x) with microwave-discharged oxygen in a fast-flow system. With the help of ab initio calculations of Yang Khandogin et al. (to be published in J. Mel. Spectrosc.) the bands were identified to be fine structure transitions (X) over tilde(2)A '' --> (X) over tilde(1)A' and (X) over tilde(3)A' --> (X) over tilde(1)A' between the components of the strongly split (3)A '' ground state of the as yet unknown bismuth hydroxide radical BiOH (BiOD). (C) 1997 Academic Press.