Developing correlation-consistent numeric atom-centered orbital basis sets for krypton: Applications in RPA-based correlated calculations.

This article focuses on the development and validation of valence-correlation-consistent numeric atom-centered orbital (NAO-VCC-nZ) basis sets for the heavy element krypton (Kr), extending previous work limited to lighter elements. The newly constructed NAO-VCC-nZ basis sets for Kr enable systematic and reliable convergence of Random Phase Approximation (RPA) and RPA plus renormalized single excitation (rSE) correlated calculations, with minimal Basis Set Superposition Error (BSSE), which is advantageous for solid-state and bulk material simulations where BSSE corrections are challenging. Using these basis sets, the authors computed the Helmholtz free energy and derived pressure–volume (P–V) curves for face-centered-cubic Kr crystals, achieving excellent agreement with recent experimental data. The study also presents preliminary results for arsenic (As), demonstrating the transferability of the approach to other heavy elements and laying groundwork for accurate correlated electronic structure calculations in extended materials.