Photofragment spin-polarization measurements via magnetization quantum beats: dynamics of DI photodissociation

We report the electron-spin polarization of D atoms from the photodissociation of DI, at 213 nm and 266 nm, by measuring the magnetization quantum beats of the D atoms with a pick-up coil. We determine that the polarization P is large at both wavelengths (|P|∼ 1), however it is positive at 213 nm, and negative at 266 nm. These results, in both cases, are of opposite sign to calculations, which assume adiabatic dissociation along the A¹Π₁ or a³Π₁ states. We interpret these results as evidence that nonadiabatic coupling between these states needs to be included for the theoretical treatment of DI photodissociation.