3Πu1and 3Σu+1states ofK2studied by a polarization-labeling spectroscopy technique

The 3 [sup 1][Pi][sub [ital u]][l arrow][ital X] [sup 1][Sigma][sub [ital g]][sup +] and 3 [sup 1][Sigma][sub [ital u]][sup +][l arrow][ital X] [sup 1][Sigma][sub [ital g]][sup +] band systems of K[sub 2] are studied by the polarization-labeling spectroscopy method. An observation of isotope shifts of rotationally resolved lines in both systems reveals that the previous vibrational numbering in the 3 [sup 1][Pi][sub [ital u]] and 3 [sup 1][Sigma][sub [ital u]][sup +] states is incorrect by 1 and 3 vibrational quanta, respectively. An analysis is carried out for both states. We present the resulting molecular parameters that describe the 3 [sup 1][Pi][sub [ital u]] state to 55% and the 3 [sup 1][Sigma][sub [ital u]][sup +] state to 71% of their potential well depths.