Temperature Dependence of Dissociative Recombination Coefficients in Argon

Electron Temperature Dependence of the Dissociative Recombination Coefficient of Molecular Argon Ions Ar+2 with Electrons

“…The last theoretical value of the dissociative recombination coefficients calculated by Royal and Orel [8] is approximately equal to 1/3 of the experimental results. Such low values, measured in past (Lukáč [11], Biondi and Brown [41]) and also in shock tube experiments Fox and Hobson [45] and Cunningham and Hobson [46], were probably caused by small amount of impurities or by dissociation of molecular argon ions. This disagreement still remains to be resolved and may be due to another recombining process, which may be caused also by another recombining channel.…”

“…The measured values of recombination coefficients are low, but increasing from 1.2 to 5.8x10 −7 cm 3 /s with increasing gas pressure from 1.4 kP a to 11 kP a. [45] and by Cunningham and Hobson [46] when T e = T g , and with the results of Wagner and Golubovskij [10] for a dc glow-discharge but with very high electron temperature (15000−20000K) and for the partial argon recombination coefficient α Ar (2p 10 ) in Paschen notation determined from the behaviour of spectral line 912.3nm corresponding to the transition of excited atomic ions Ar * (4p) by Ivanov and Makasjuk [50]. Other partial recombination coefficients determined from another spectral lines show weaker exponential electron temperature dependences.…”

Laser-induced breakdown of gases

“…Morgan et a1 suggested that the weaker dependence on p shown by the data for argon is due to the occurrence of recombination of the higher pressures. In argon R has relatively large values N 3 x 10-7 cm3 s-1 at 300 K (Biondi 1951) decreasing rapidly with electron temperature to 2 x 10-8 cm3 s-1 at 1800 K (Fox and Hobson 1966).…”

Theory of Gas Discharge Plasma

“…We now consider ionization equilibrium in an argon gas discharge plasma with molecular ions as a basic ion type, so that the channel of electron destruction corresponds electron-ion dissociative recombination according to the scheme e + Ar + 2 → A + A * , (11.3.8) and the ionization balance equation takes the form in the regime of low electron number densities k ion N a = α N e (11.3.9) Here k ion is the rate constant of single ionization of argon atoms by electron impact which values are given in Table 8.1, and α is the coefficient of dissociative recombination. Statistical averaging of measured data [214,309,424,425,[427][428][429][430][431] gives for the dissociative recombination coefficient at room temperature α(Ar + 2 ) = (7 ± 2) · 10 −7 cm 3 /s…”