Role of picture change correction in relativistic density functional theory: an analogy with coupled cluster theory

Abstract Relativistic density functional theory (RDFT) plays a vital role in electronic structure calculations of heavy-element compounds, where accurate electron density evaluation is essential. We demonstrate that picture change correction (PCC) in RDFT is conceptually analogous to corrections in coupled-cluster theory and that neglecting PCC leads to inconsistencies in electron density evaluation. This work underscores the need to incorporate PCC in RDFT to improve accuracy. Future research should focus on developing computationally efficient schemes to implement PCC without significantly increasing the cost of RDFT calculations.