MoLe-{Lambda}: Learning the Coupled-Cluster Response State for Energies, Gradients, and Properties

arXiv:2605.29622v1 Announce Type: new Abstract: Coupled-cluster (CC) theory is often considered the gold standard of quantum chemistry, but its high computational cost limits routine access to accurate energies, forces and response properties. While the right-hand T-amplitudes determine the correlated wavefunction, many practically important observables additionally require the left-hand Lambda-amplitudes. We introduce MoLe-Lambda, an extension of Molecular Orbital Learning (MoLe) that predicts the full ground-state coupled-cluster singles and doubles (CCSD) response state by jointly learning right-hand amplitudes (T_1,T_2) and left-hand amplitudes (Lambda_1,Lambda_2) from localized Hartree--Fock molecular orbitals. Architecturally, MoLe-Lambda extends MoLe with Lambda_1 and Lambda_2 readouts that mirror the symmetry constraints of the T_1 and T_2 heads, while preserving the original equivariant orbital encoder, odd sign-equivariant decoding, locality and size-extensivity. The resulting model yields accurate CC-quality energies and forces, while simultaneously recovering dipoles, quadrupoles, polarizabilities, the electron density, and 2-electron observables such as the pair density. We show that MoLe-Lambda further extends the speed advantage of MoLe over full CCSD while substantially expanding the accessible properties, providing a route to wavefunction-level surrogate models for correlated quantum chemistry.

Source: arXiv cs.LG | 2026-05-29