Spectroscopic Examination of Fulcher-α Band of Microwave Discharge H2-D2 and H2-He Plasmas

We examine Fulcher-α band spectrum of microwave discharge H2/D2 plasmas with their discharge pressure about 1 Torr, and determine rotational and vibrational populations of the upper state of the Fulcher-α band, d 3Πu state. It is found that the rotational temperature becomes lower with increasing vibrational quantum number, and that its dependence is stronger for H2 plasma than for D2 plasma. Rotational and vibrational temperatures are examined as functions of H2/D2 mixture ratio in the feed gas, which reveals that high partial pressure of D2 increases the rotational temperatures for constant total discharge pressure, except for pure D2 discharge.