  Parity violation experiment in Yb is made on the strongly forbidden M1
transition 6s^2 1S0 \to 5d6s 3D1. The hyperfine mixing of the 5d6s 3D1 and 5d6s
3D2 levels opens E2 channel, whose amplitude differs for F-sublevels of the 3D1
level. This effect may be important for the experimental search for the
nuclear-spin-dependent parity violation effects predominantly caused by the
nuclear anapole moment.
