Relativistic semistochastic heat-bath configuration interaction

In this work we present the extension of semistochastic heat-bath configuration interaction (SHCI) to work with any two-component and four-component Hamiltonian. Vertical detachment energy (VDE) of AuH_2^- and zero-field splitting (ZFS) of NpO2 2+ are calculated by correlating more than 100 spinors in both cases. This work demonstrates the capability of SHCI to treat problems where both relativistic effect and electron correlation are important.