Differential cross sections at 0° and 180° for electron-impact excitation of the E ³Σ_g⁺ state of N₂

Relative differential cross sections at forward and backward angles for excitation of the E ³Σ_g⁺ state of N₂ have been measured in the resonant, near threshold energy region. Measurements are performed by using a double trochoidal electron spectrometer and are calibrated on the absolute scale by simultaneous measurements of this process and vibrational excitation of the ground state of N₂ via ²Π_g resonance. The contributions at 0° and 180° are separated by electron beam modulation and time-of-flight detection of scattered electrons. Obtained results confirm directly theoretical predictions of the symmetry of angular distribution of scattered electrons from ²Σ_u⁺ resonance.