A new absorption band of BaH at 2991 Å

A new band of BaH at 2991 A has been observed in absorption in the third order of a 21 ft concave grating spectrograph. The band is shown to be the (0, 0) band of BaH belonging to a new electronic transition which may be calledI2Σ-X2Σ. The rotational constants of the upper state have been evaluated and are given below:B 0 ′ =3.19 cm−1,D 0 ′ =1.12·10−1,v0,0=33415.7 cm−1.