Analysis of the transition B2Σ+-X2Σ+in gaseous LaS

Abstract
Bands of gaseous LaS have been observed in thermal emission and in absorption, and the vibrational analysis of one system B2 Sigma -X2 Sigma + in the region 7000 to 8500 AA has been obtained, together with the rotational analysis of the 0-0 band. The bands possess four R and Four P branches, and the splittings can be interpreted in terms of (i) a large spin splitting gamma (N+1) in the upper state, (ii) a J independent case bbeta s nuclear magnetic hyperfine interaction in the ground state whose magnitude is within experimental error the same as in LaO.