SPIN-CONVERSION RELAXATION IN DIMETHYL-S-TETRAZINE DOPED N-OCTANE - DEUTERATION AND SYMMETRY-BREAKING

Spectral hole burning is used to measure spin-conversion relaxation of methyl groups attached to a dye probe. The dye is dimethyl-s-tetrazin e, the host is n-octane, which is, at low temperatures, a Shpol'skii-m atrix. The temperature dependence of the spin-conversion relaxation fo llows the same pattern for the protonated and the perdeuterated methyl -rotor. However, the relaxation rates of the perdeuterated rotor are h igher by almost two orders of magnitude. Partial deuteration destroys the rotor symmetry and leads to a breakdown of the correlation between nuclear spin and rotational wave function.