The Effective Collision Frequency in Molecular Hydrogen in the Presence of a Transverse Magnetic Field

The effective electron molecule collision frequency ν is evaluated for hydrogen from pre-breakdown ionization measurements in crossed electric and magnetic fields. A constant value ν = 2.5 × 10 9 p sec -1 is obtained for all values of the parameters 100 < E/p < 250 V cm -1 mmHg -1 and 0 < H/p < 300 Oemm Hg -1 in agreement with the basic assumption underlying the formulation of an equivalent pressure concept for the influence of a transverse magnetic field in hydrogen. An error analysis is used to illustrate the problems associated with a determination of accurate values of ν at low values of E/p in the presence of small magnetic fields.