This paper presents the measured values of the total dissociative recombination coefficient of molecular Ar + 2 ions with electrons α(Ar + 2 ) as a function of both electron and gas temperatures. The measured recombination coefficient can be expressed as α Ar + 2 (T e , T gas ) = (8.1 ± 0.5) × 10 −7 (T e /300 K) −0.64 (T gas /300 K) −0.86 cm 3 s −1 in the temperature ranges 300 K T e 10 400 K and 300 K T gas 500 K.

Key words Stationary afterglow plasma, microwave diagnostics of plasma, electron heating with microwaves, dissociative recombination, electron temperature dependence of recombination, molecular argon ions.A dual mode (T M 010 cylindrical cavity/cylindrical waveguide) microwave apparatus is used to study the ion mobility and dissociative recombination of molecular argon ions with electrons in the afterglow period of a d.c. glow discharge as a function of electron temperature when electrons were heated by microwaves up to Te ≤ 10300 K, with T+ = Tgas = 300 K. The electron temperature dependence of the total rate coefficient of dissociative recombination may be represented by α(Arwhich is in very good agreement with most previous experimental results but not with the recent theoretical calculations.

Key words Stationary afterglow plasma, microwave diagnostics of plasma, electron heating with microwaves, dissociative recombination, electron temperature dependence of recombination, molecular neon ions. PACS 34. 80, 52.20, 52.70 Three dual mode microwave apparatus (one using S-band and two using X-band) have been developed to determine ambipolar diffusion and electron-ion recombination rates under conditions such that Tgas = 300K and Te is varied from 300 K to 6300 K, in the afterglow period of the dc glow discharge. The T M010 cylindrical cavity (in S-band) and T M011 open cylindrical cavity (X-band) are used to determine the electron density during the afterglow period and a non-resonant waveguide mode is used to apply a constant microwave heating field to the electrons. To test the properties of the apparatus the neon afterglow plasma has been investigated. At Te = 300 K a value of α(Ne (X-band) obeyed over the range 300 ≤ Te ≤ 6300K are in good agreement with some other previous measurements. The simplicity of the X-band microwave apparatus also allows the measurements of the gas temperature dependency and the study of electron attachment and may be used simultaneously with optical or mass spectrometry investigations.

This paper presents the measured values of the total dissociative recombination coefficient of molecular neon ions α (Ne + 2 ) as a function of both electron and gas temperatures. The measured recombination coefficient can be expressed as α Ne + 2 (T e , T g ) = (1.8 ± 0.2) × 10 −7 (T e /300 K) −0.42 (T g /300 K) −0.7 cm 3 s −1 in the temperature ranges 300 K T e 6300 K and 300 K T g 500 K.

Microwave heating of the electrons with the non-resonant TE11 circular waveguide mode is used to study the dependence of the dissociative recombination coefficient in krypton. Electron density during the glow discharge afterglow is determined from measurements of the resonant frequency shift of the high-Q TM010 or TE111 cavity mode. In the electron temperature range 300-21300K and with neutral gas temperature equal to 300K the recombination coefficient may be represented as alpha (Kr2+)(cm3 s-1)=1.48*10-6 (Te/300K)-0.53. The measured recombination coefficient is independent of the krypton gas pressure in the range 3-12 Torr.