Chemiluminescence and rotational alignment in Mn*(a 4DJ, a6DJ) + SO2 → MnO*(A′ 6Π, A6Σ+) + SO†
Abstract
Measurements with ‘hot’ and ‘cold’ Mn atom beams, and analysis ia the multiple line-of-centres procedure, have enabled the determination of separate state-to-state translational excitation functions for Mn*(a4DJ, a6DJ) + SO2
→ MnO*(A′6Π, A6Σ+) + SO. All indicate either a narrow cone of acceptance for reaction or a fairly flat angular dependence of the barrier, a result also inferred from ab initio density functional theory calculations on the lowest quartet surface. With increasing collision energy, the barrier appears to shift forward, suggesting a transition from ‘ soft-sphere’ to ‘ hard-sphere’ dynamics. For Mn*(a4DJ) → MnO*(A6Σ+)
the rotational alignment −
〈P2(ĵ′·
)〉 at first falls with increasing collision energy, indicating preferred coplanar reaction geometry, but this preference is absent in all other channels. Simple molecular orbital–