Changelog

All notable changes to the HUMMR code are documented here.

v1.0 - 23 September 2025

This is the first release of the HUMboldt MultiReference (HUMMR) code.
It includes the following features/modules:

• MCSCF

  • Rigorously spin-adapted
  • Full-CI and Heatbath-CI Solver
  • First order and (full-) second Order Orbital Optimizer
  • State-averaged nuclear gradients
  • Non-adiabatic couplings

• Dynamical Electron Correlation

  • SC-NEVPT2
    • Quasi-degenerate formulation
    • Epstein–Nesbet NEVPT2
  • AC0

• Integral handling

  • Lible: Open-access implementation of SHARK
  • Comprehensive usage of density fitting

• Spin-orbit coupling

  • QDPT
  • Available for MCSCF and SC-NEVPT2
  • Molecular g-tensors

• ASS1ST

  • Active space selection
  • Active space refinement

• Solvation / Embedding

  • C-PCM (with Gaussian charge distributions)
  • Pointcharge embedding