Rotational anisotropy and product state distribution in the photodissociation of deuterium peroxide

Nascent OD(X ²Π_i) radicals, generated in the photodissociation of D₂O₂ at 266 nm, have been probed by laser-induced fluorescence. The observed line intensities exhibit a marked dependence on excitation-detection geometry and laser polarisation, indicating rotational alignment (A_o⁽²⁾ ⩽ 0.28). The analysed product rotational distributions and Doppler width measurements indicate that the fragment energy partitioning (f_kin = 0.86,f_rot = 0.14) is too different from that reported for H₂O₂ photodissociation to explain the isotopic process by energy arguments alone.