  The existence of the fundamental CP-violating interactions inside the nucleus
leads to the existence of the nuclear Schiff moment. The Schiff moment
potential corresponds to the electric field localized inside the nucleus and
directed along its spin. This field can interact with electrons of an atom and
induce the permanent electric dipole moment (EDM) of the whole system. The
Schiff moment and corresponding electric field are enhanced in the nuclei with
the octupole deformation leading to the enhanced atomic EDM. There is also a
few-order enhancement of the T,P-violating effects in molecules due to the
existence of energetically close levels of opposite parity. We study the Schiff
moment enhancement in the class of diatomic molecules with octupole-deformed
lanthanide and actinide nuclei: $^{227}$AcF, $^{227}$AcN, $^{227}$AcO$^+$,
$^{229}$ThO, $^{153}$EuO$^+$ and $^{153}$EuN. Projecting the existing
experimental achievements to measure EDM in diamagnetic molecules with
spherical nucleus ($^{205}$TlF) to the considered systems one can expect a very
high sensitivity to the quantum chromodynamics parameter ${\bar \theta}$ and
other hadronic CP-violation parameters surpassing the current best limits by
several orders of magnitude. It can have a dramatic impact on the modern
understanding of the nature of CP-violating fundamental interactions.
