An adiabatic chemiluminescent reaction: N(2D) + H2 → NH(A3Π) + H, studied under beam conditions

The title reaction has been studied spectroscopically, using N(2D) atoms (15–100 eVlab) generated by N+ + Xe charge transfer. At 5 eVCM the cross-section is ∼7 times greater than for the analogous N(4S) reaction measured previously, due to an adiabatic pathway which exists only in the former case. Simulations of the NH(A2Π–X3Σ−) spectra show up to 4 eVCM equilibrated rovibrational distributions. This indicates an insertion-type reaction, consistent with ab initio calculations. At high energy, rotation and vibration become uncoupled and non-thermal, suggesting a two-body impulsive mechanism.