Assuming the active molecule as a two-level system, we calculate the r
acemization, due to the tunneling effect, taking into account the effe
cts of the weak interactions and of an external potential. We show tha
t the weak interactions would block the tunneling racemization of enan
tiomers in compressed gases and liquids. Chirality 10:519-521, 1998. (
C) 1998 Wiley-Iiss, Inc.