We measured vibrational temperature Tv and rotational temperature Tr of CO b 3Σ+ state, which was
observed for the transition to the a 3Πr state as 3rd positive system in microwave discharge CO2
plasma, and particularly, examined effects of a rare gas (He, Ar, and Kr) admixture on them. When
Kr was mixed into it with a considerable amount, the vibrational temperature increases higher than
other rare gases.