  We consider the effects of multistate transitions on the tunneling
racemization of chiral molecules. This requires going beyond simple two-state
models of enantiomers and to include transitions within a multiple-level
quantum-mechanical system.We derive an effective two-level description which
accounts for transitions from the enantiomers to an arbitrary number of excited
states as an application of the Weisskopf-Wigner approximation scheme.
Modifications to the optical activity from these additional states are
considered in general terms under the assumption of \textit{CPT} invariance and
then under T invariance. Some formal dynamical analogies between enantiomers
and the neutral K-meson system are discussed.
