Collision transfers between CdH A 2Πυ′ = 0 rotational states induced by He or Ar

CdH is obtained by radiofrequency discharge in Cd vapor mixed with 5% H₂ in He or Ar. It is selectively excited by a pulsed dye laser to A ²Π_{$\text{1}\text{2}$,$\text{3}\text{2}$} υ′ = 0, J′ = 0.5–16.5. Collision cross sections are measured from several J′ values corresponding to rotational transfers observed up to ΔJ′ = ±7. The total collision cross sections are smaller with He than with Ar. They decrease as J′ increases. The levels of the same electronic parity as the initial level are strongly privileged for high J′ with He, much less with Ar. The polarization of the initial lines decreases appreciably for high J′ with the Ar pressure, much less with the He pressure. Small spin transfers are observed from Π_{$\text{3}\text{2}$} to Π_{$\text{sol:1}\text{2}$}. The experimental results, especially the propensities, are justified using the Born approximation as developed in previous papers. Its validity is discussed in comparing the effects of He and Ar.