Rate Coefficient for $X^{+}+2X\to X_2^{+}+X$ in Neon and Argon

A method is described of determining three-body conversion coefficients for the production of homonuclear diatomic ions. The technique involves ion sampling from the positive column of a dc discharge. For neon, values of the rate coefficient vary from 5.7-8.9×${10}^{-32\mathrm{}}$ ${\mathrm{cm}}^6$/sec depending on the values of a number of experimental parameters. In argon values range from 3.0-4.7×${10}^{-31\mathrm{}}$ ${\mathrm{cm}}^6$/sec. The present results are compared with values obtained using other techniques.