Nuclear-Electronic Orbital Ab Initio Wavefunction Methods in Q-Chem

Explore advanced nuclear-electronic orbital (NEO) ab initio wavefunction methods in this 59-minute webinar presented by Jonathan Fetherolf from Princeton University. Learn how NEO approaches incorporate nuclear quantum effects such as zero-point energy and hydrogen tunneling directly into electronic structure calculations by treating select nuclei, typically hydrogen atoms, at the same theoretical level as electrons. Discover the latest developments in NEO coupled cluster (NEO-CC) theory, which provides a pathway to "gold standard" reference calculations capable of accurately capturing ground-state properties including nuclear delocalization and anharmonic zero-point energy. Examine NEO-CC with singles and doubles alongside more approximate methods such as orbital-optimized MP2 and second-order coupled cluster (CC2). Understand how excited states and multireference problems present additional challenges for NEO methods, and explore the recently developed NEO multireference configuration interaction (NEO-MRCI) approach that produces high-quality excitation energies and tunneling probabilities for complex systems. Gain insights into how these advanced computational methods advance beyond previously presented density functional theory and time-dependent DFT approaches for incorporating nuclear quantum effects in chemical and biological processes.