Momentum-Transfer and Inelastic-Collision Cross Sections for Electrons in ${\mathrm{O}}_2$, CO, and C${\mathrm{O}}_2$

Momentum-transfer and inelastic-collision cross sections for electrons in ${\mathrm{O}}_2$, CO, and C${\mathrm{O}}_2$ are calculated from measured values of the electron drift velocity, characteristic energy, attachment coefficient, and ionization coefficient. The experimental data for ${\mathrm{O}}_2$ are most consistent with vibrational excitation cross sections consisting of a series of resonances located at the vibrational energy levels of the negative ion and having values of cross section times energy half-width of the order of ${10}^{-18\mathrm{}}$ ${\mathrm{cm}}^2$ eV. The calculated effective dipole moment for rotational excitation of CO is in very good agreement with values obtained by other techniques. The vibrational excitation cross section for CO at electron energies below 1 eV is in agreement with theoretical predictions. The vibrational excitation cross sections required for consistency with the C${\mathrm{O}}_2$ data are very large [(2-5) × ${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$] and include a peak very close to the vibrational threshold of 0.083 eV.