Stereodynamics of photon-induced reactions via Doppler-resolved laser-induced fluorescence spectroscopy: photodissociation of HONO2 and the reaction of O(1D) with CH4

Abstract

The application of polarised, Doppler-resolved laser-induced fluorescence (LIF) probing of the products scattered from photon-induced ‘half-collision’(photodissociation) and ‘full-collision’(bimolecular reaction) processes is developed to include the velocity dependence of their stereodynamics. Fourier-transform inversion procedures are used to derive the products' speed distributions W(v′) and vector correlations β_ij(v′)(a) in the photodissociation of HONO₂ and (b) in the bimolecular reaction of O(¹D) with CH₄. In the former example, they provide new insight into the stereodynamics of the photodissociation, HONO₂+hν→ HO(v= 0, N)+ NO₂(X, Ã) In the latter, together with newly developed LAB → CM simulation methods, they provide new insight into the stereodynamics of the reaction, O(¹D)+ CH₄→ OH(v= 4, N)+ CH₃ The OH is shown to be generated with its rotational angular momentum j′, constrained to lie in a plane directed perpendicular to its centre-of-mass relative velocity, k′.