Photodissociation dynamics of HNO3 at 266 nm

초록

The photodissociation dynamics of HNO<inf>3</inf> at 266 nm has been investigated by measuring laser induced fluorescence spectra of the OH (2H) fragments. The measured fractions of the available energy distributed among the fragments are f<inf>t</inf> = 0.21, f<inf>r</inf>(OH) = 0.047, f<inf>int</inf>(NO<inf>2</inf>) = 0.74, and negligible OH fragments are found in the vibrationally excited states. By analyzing Doppler profiles of the spectra, vector correlations in the photodissociation of HNO<inf>3</inf> have been measured. The measured correlations show that the transition is parallel (β<inf>μν</inf> = 1.0) but the transition dipole moment and the recoil velocity of the fragment are not exactly parallel. The rotational angular momentum J of the product OH is aligned parallel to the recoil direction of the fragment. From the measured correlations and the large fraction of the internal energy in the NO<inf>2</inf> fragments, it has been concluded that the transition at 266 nm is described as vibronic to the pyramidal excited state of A″ symmetry. Together with the measured A-doublet distribution of the OH fragments, the dynamics of photodissociation is discussed in detail. © 1997 Elsevier Science S.A.

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