PNNL

Abstract

Nuclear quantum e?ects play an important role in the structure and thermodynam-ics of aqueous systems. By performing a many-body expansion with nuclear-electronic orbital (NEO) theory, we show that proton quantization leads to long-range energetic e?ects in single-point energy calculations of water clusters. Although zero-point mo-tion produces a large increase in energy at the one-body level, nuclear quantum e?ects serve to stabilize molecular interactions at higher orders. These results are signi?-cant because they demonstrate that nuclear quantum e?ects play a nontrivial role in many-body interactions of aqueous systems. Our approach also provides a pathway to incorporate nuclear quantum e?ects into water potential energy surfaces. The NEO ap-proach is advantageous for many-body expansion analyses because it includes nuclear quantum e?ects directly into the energies.