PARITY VIOLATION EFFECTS IN DIATOMICS

Discussion of the parity violation and the break of the time-reversal invariance in diatomic molecules has continued for a number of years. Experiments on the TIF molecule gave one of the most stringent limits on the electric-dipole moment of the proton and on the T-violating nuc lear forces. At present, a new generation of experiments with paramagn etic diatomic molecules is underway. These experiments are aimed mainl y at the search for the electric-dipole moment of the electron. In thi s topical review we examine theoretical aspects of parity non-conserva tion in diatomic molecules. We focus on molecular theory leaving aside the nuclear part of the problem. In this approach the nucleus is char acterized by the number of P-odd and P, T-odd moments, namely anapole moment, Schiff moment and magnetic quadrupole moment. Molecular theory has to link these moments to the experimentally measured quantities, such as frequency shifts, etc. The other possible sources of the parit y non-conservation in molecules are the electron-nuclear neutral curre nt interactions and the electric-dipole moment of the electron. They a re also discussed in this review.