The first identification of lines from the FeH molecule was made in the blue-green part of the solar spectrum by Carroll & McCormack (1972). The molecular origin of a number of weak lines was also demonstrated by the fact that their strengths were enhanced in sunspots (Moore et al. 1966). Klynning & Lindgren (1973) reported that lines of the (0-0) band of FeH extend from 9 896 Å to at least 10 205 Å. Carroll et al. (1976) detected a number of coincidences between laboratory lines of FeH and weak unidentified solar lines, again in the blue and green wavelength region, in addition to the infrared. Wing et al. (1977) confirmed the presence of the (0-0) and (1-0) bands of iron hydride in sunspots and cool stars. They were not be able to identify the infrared FeH bands in the spectrum of the solar disk. Wöhl et al. (1983) measured the strengths of the (0-0) and (1-0) bands of the FeH molecule in the umbral spectrum of a large spot.
It is noticed that the sunspot spectrum from 9 900 Å to 10 100 Å\
comes close to being a pure FeH spectrum. Since very high resolution
solar and laboratory spectra are available,
a reinvestigation of the FeH
molecule is, therefore, of notable interest.