Crossed beam studies of elementary reactions of N and C atoms and CN radicals of importance in combustion
Abstract
The dynamics of some elementary reactions of N(2D), C(3P,1D) and CN(X2Σ+) of importance in ia two competing pathways leading to HNO + H and HON + H, while formation of NO + H2 is negligible. Formation of H + H2CCCH (propargyl) is the dominant pathway, at low collision energy (Ec), of the C(3P) + C2H4 reaction, while at high Ec formation of the less stable C3H3 isomers (cyclopropenyl and/or propyn-1-yl) also occurs; the H2 elimination channel is negligible. The H elimination channel has also been found to be the dominant pathway in the C(3P,1D) + CH3CCH reaction leading to C4H3 isomers and, again, no H2 elimination has been observed to occur. In contrast, both H and H2 elimination, leading in comparable ratio
to C3H + H and C3(X1Σg+) + H2(X1Σg+), respectively, have been observed in the reaction C(3P) + C2H2(X1Σg+). The occurrence of the spin-forbidden molecular pathway in this reaction, never detected before, has been rationalized by invoking the occurrence of intersystem crossing between triplet and singlet manifolds of the C3H2 potential energy surfaces. The reaction CN(X2Σ+) + C2H2 has been found to lead to internally excited HCCCN (