A beam experiment on the energy transfer reaction NO(a4Π)+NO(X2Π)→NO(X2Π)+NO(A2Σ+)

Collision-induced NO(A 2Σ+→X 2Π) emission was observed upon passage of a molecular beam containing the metastable NO(a 4Π) species through a cell filled with NO gas. Low target gas pressure (6 m Torr) ensured single-collision conditions. The collisional energy transfer NO(a)+NO→NO+NO(A) was shown to be intermolecular by comparison with other target gases. For its cross-section, an estimate of ∼2 Å2 was obtained by calibration against the reaction N2(A)+NO→N2+NO(A), observed using the same beam source and target conditions.