Periodic trends in parity-violating hyperfine coupling constants of open-shell diatomic molecules

Abstract

Nuclear spin-dependent parity violation effects are predicted with the help of a quasi-relativistic two-component zeroth order regular approximation (ZORA) approach for a series of open-shell diatomic molecules that feature a 2Σ electronic ground state. The particular focus is on scaling behaviour of the parity violating parameter Wa in the effective spin-rotational Hamiltonion with increasing nuclear charge Z of the heavier atom in the diatomic molecule. Previously (Isaev and Berger, 2012) an approximate R(A,Z)Z2 scaling law, with R(A,Z) denoting a relativistic enhancement factor, was confirmed for Wa in the series of valence isoelectronic group II monofluorides and valence isoelectronic group XII monohydrides, that is along columns of the periodic table of the elements. In this work, a pronounced R(A,Z)Zk scaling is predicted for isolobal 2Σ diatomic molecules along rows of the periodic table, with k being approximately 4 and 6 for the fourth and fifth row, respectively, and even larger for the sixth and seventh row. This observation opens up a another dimension in the systematic search of candidate systems for measuring nuclear spin-dependent parity violating interactions in molecules.