  Nuclear magnetic quadrupole moments (MQMs), like intrinsic electric dipole
moments of elementary particles, violate both parity and time-reversal symmetry
and therefore probe physics beyond the Standard Model of particle physics. We
report on accurate relativistic coupled cluster calculations of the nuclear MQM
interaction constants in BaF, YbF, BaOH, and YbOH. We elaborate on estimates of
the uncertainty of our results. The implications of experiments searching for
nonzero nuclear MQMs are discussed.
