Forte2

Forte2 is a standalone, open-source suite of quantum chemistry methods that focuses on multireference and relativistic methods.

Current capabilities include:

• Exact-two-component relativistic Hamiltonians with spin-orbit coupling
• Non-relativistic and relativistic SCF (RHF, ROHF, UHF, GHF)
• CI methods, including spin-adapted CI, GAS/ORMAS, relativistic CI, and heat-bath CI
• MCSCF (CAS/GAS/ORMAS) with state averaging, and relativistic variants
• Active-space selection (AVAS) and embedding methods (ASET)
• DSRG-MRPT2, non-relativistic and relativistic

VibeMol

VibeMol is a molecular visualization app that runs in the browser. It renders molecular orbitals and densities from cube files and molecular geometries from XYZ files, with no installation required.

• Surface and cloud rendering of orbitals, including two-component cube files
• Several molecule styles, plus edit and measurement modes
• Playback of vibrational modes from Psi4 and ORCA outputs
• A calculations mode that generates Forte2 AVAS input
• VS Code extension

Wick&d

Wick&d is a Python library for the algebra of second quantization for fermionic systems. It implements Wick's contraction theorem for general Fermi vacua, which makes it well suited for deriving the equations of quantum chemistry methods such as coupled cluster, many-body perturbation theory, and multireference theories.

See the examples for worked derivations, such as the coupled cluster equations.

QForte

QForte is a development tool for new quantum simulation algorithms that also contains black-box implementations of a wide variety of existing ones. It handles molecular Hamiltonians, fermionic encoding, automated ansatz construction, time evolution, state-vector simulation, operator averaging, and computational resource estimation, and requires only a classical electronic structure package as a dependency.

Algorithms include:

• Unitary coupled cluster variational and projective quantum eigensolvers (VQE, PQE) and ADAPT-VQE
• Selected projective quantum eigensolver (SPQE)
• Single-reference and multireference quantum Krylov diagonalization
• Quantum imaginary time evolution and quantum Lanczos

Forte

Forte is an open-source plugin to Psi4 that implements a variety of quantum chemistry methods for strongly correlated electrons.