Collision Cross Sections of Hydrogen and Other Ions as Determined by Ion Cyclotron Resonance

Through determinations of the widths of ion cyclotron resonance lines as a function of pressure and electric field strengths, the ion—molecule collision cross sections of H+, H2+, H3+, He+, Ar+, N2+, N+, O2+, O2−, and O− were obtained. Agreement with dc mobility data was found. In particular, the minimum in collision frequency for H3+ in H2 at E/P0=60 V/cm·torr was confirmed. The cross sections for H2+ in H2 are 275 and 68 Å2 at low and high E/P, respectively.