AbstractThe reaction rate values for the molecular nitrogen B3IIgstate quenching by ethanol for vibrational quantum numbersv′ = 4–12 have been evaluated from the change of N2first positive system spectrum at ethanol addition to a high speed, microwave produced, plasma flow. The wall influence is avoided using a 0.9 m large reaction chamber. Computed N2(B3IIg) quenching rate values are comprised between 0.9 × 10−10and 1.4 × 10−10cm3· s−1, being smaller than the corresponding gask