Chemiluminescence and rotational alignment in Mn + O2: Direct observation of the MnO*(A′6Π) state†
Abstract
‘Hot’ and ‘ cold’ beam chemiluminescence excitation functions have been determined for the Mn + O2 reaction in the 560–700 nm (‘red ’) and 770–900 nm (‘ia two distinct potential surfaces to yield both MnO* emitting states in common processes. A more excited metastable state also generates products, but the lower z8PJ state
yields A 6Σ+ chemiluminescence only. The product rotational alignments 〈P2( ĵ′·
)〉 in the higher-threshold processes are initially high, reflecting a line-of-normals energy dependence in which the relative velocity k lies at first in the Mn–O–O plane. For a4DJ atoms, the initial A′6Π alignment is lower than that of A6Σ+, suggesting that the former requires either near-linear or C2v geometry, and the latter less restricted configurations, on the same potential surface.