LINEARLY VARYING LEVEL MODEL OF CIDEP GENERATED BY INTERSYSTEM CROSSINGS

Chemically induced electron spin polarization due to nonadiabatic transitions between spin levels of a pair of paramagnetic molecules is treated by assuming the level separation varies linearly with lime during diffusive passage of the pair through the level crossing. If the spin levels are widely separated outside the crossing region, this model gives the same polarization as the stochastic Liouville model, and a better physical picture of the process. The case of a rapidly varying level-mixing interaction, such as the dipolar interaction in the triplet member of a triplet-doublet pair, is also treated.