LINEARLY VARYING LEVEL MODEL OF CIDEP GENERATED BY INTERSYSTEM CROSSINGS

Chemically induced electron spin polarization due to nonadiabatic tran sitions between spin levels of a pair of paramagnetic molecules is tre ated 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 g ives the same polarization as the stochastic Liouville model, and a be tter physical picture of the process. The case of a rapidly varying le vel-mixing interaction, such as the dipolar interaction in the triplet member of a triplet-doublet pair, is also treated.