ROTATIONAL ANALYSIS OF A $^{2}\Pi\rightarrow^{2}\Delta$ ELECTRONIC TRANSITION IN LaO

Abstract

Rotational analysis of two LaO violet-degraded band systems between 6500 and 6825 {\AA} has shown they are sub-bands of a $^{7}\Pi\rightarrow^{2}\Delta$ electronic transition. The analysed $^{2}\Pi$ state is neither the $A^{2}\Pi$ nor $C^{2}\Pi$ state known from transitions to the X state. The $^{2}\Delta$ state is probably the expected low-lying state derived primarily from a (La $d\delta$) molecular orbital configuration.