Alignment dependence of the NH₂ chemiluminescence in the reaction of Ar(³P) Atoms with the aligned NH₃ molecules

An alignment dependence of the NH₂(Ã-X̃) chemiluminescence was studied in the reaction of the aligned NH₃ molecules and the metastable Ar(³P) atoms by using hexapole state selection. The NH₂ emission intensities were analyzed by a hard-sphere model for the NH₃ molecule. The ratio of the emission cross sections for the head-on attack and the side-on attack was found to be σ_h/σ_s = 1.2 ± 0.2. The observed alignment dependence is discussed in terms of the interaction between molecular orbitals of NH₃ and the atomic orbital of Ar(³P).