Abstract
The D1 Pi -X1 Sigma (3200-4000 AA) system of SnO is excited in a vertical arc source. Relative band intensities are measured using the technique of photographic photometry and interpreted with the aid of Franck-Condon factors qv'v". It is found that the electronic transition moment varies as Re(r)=const (1-1.119r+0.356r2) where 1.8v"I/v4 against G'(v') for v'=0, 1, 2, 3,... is made and the effective vibrational temperature is estimated as 1100 K.