Observation of the fluorescence polarization of atomic fragments from rotational resolved predissociation

The effect of molecular rotation on the degree of polarization of the fluorescence emitted by H-atoms that are obtained by photopredissociation of H₂ into H(n=3)+H(1S) has been observed. The H₂ molecules are excited to predissociative excited states with a well defined rotational quantum number by absorption of a photon in the wavelength range of 720–750 Å. The molecular rotational motion is clearly seen to reduce the polarization. In one case the polarization vanishes, which is attributed to aP(1) rotational line of a¹–¹ transition, which cannot be explained classicially. Quantum mechanical calculations with relatively simple expressions and explicit values of the polarization of atomic fluorescence are presented.