CH3 RADICAL DENSITY IN ELECTRON-CYCLOTRON-RESONANCE CH3OH AND CH3OH/H-2 PLASMAS

CH3 radical densities in electron cyclotron resonance (ECR) discharge methanol (CH3OH), methanol diluted with hydrogen gas (CH3OH/H-2) and methane (CH4) plasmas were measured for the first time using infrared diode laser absorption spectroscopy (IRLAS). CH3 radical densities in the CH3OH and CH3OH/H-2 plasmas were estimated to be of the order of 10(11) cm(-3) under the conditions of total pressure of 1.3 Pa and microwave power of 50-800 W. On the other hand, CH3 radical density in the CH4 plasma was estimated to be less than 10(10) cm(-3). Moreover, the production and loss processes of CH3 radical in the CH3OH plasma were discussed on the basis of the results of emission intensity of Ar*, the absorption ratio of CH3OH molecule and the decay curve analysis of CH3 radical after termination of the discharge.