Resonant electron-molecule scattering: The impulse approximation inN2O

${\mathrm{N}}_2$O is a linear triatomic molecule. Electron scattering shows a ${}_{}{}^2{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}$ shape resonance at ∼ 2.3 eV. The lifetime turns out to be so short, 0.9 × ${10}^{-15\mathrm{}}$ sec, that one has an impulse picture, in which the nuclei acquire velocity but suffer little displacement during the residence of the projectile electron. The nuclear wave equation at the resonance is solved in the impulse approximation, and is shown to give a good account of the excitation of more than 20 vibrational states observed by Azria, Wong, and Schulz.