===================
Acronym definitions
===================

.. glossary::

   AO
      Atomic Orbital.

   API
      Application Programming Interface.

   ASCI
      Adaptive Sampling Configuration Interaction.

   AVAS
      Automated Valence Active Space.
      Method that projects molecular orbitals onto a target atomic orbital basis to identify valence active orbitals.

   BFGS
      Broyden-Fletcher-Goldfarb-Shanno quasi-Newton optimization algorithm.

   BSE
      Basis Set Exchange, a repository of standardized quantum chemistry basis sets and effective core potentials.

   CAS
      Complete Active Space.

   CASCI
      Complete Active Space Configuration Interaction.

   CASSCF
      Complete Active Space Self-Consistent Field.

   CCSD
      Coupled Cluster with Single and Double excitations.

   CCSD(T)
      Coupled Cluster with Single and Double excitations and perturbative Triple excitations.

   CI
      Configuration Interaction.

   CNOT
      Controlled-NOT two-qubit gate used in quantum circuits.

   CODATA
      Committee on Data of the International Science Council, which publishes recommended values of fundamental physical constants.

   DFT
      Density Functional Theory.

   DIIS
      Direct Inversion in the Iterative Subspace.

   ECP
      Effective Core Potential, a pseudopotential that replaces core electrons to simplify calculations.

   ERI
      Electron Repulsion Integral.

   FCI
      Full Configuration Interaction.

   FCIDUMP
      Text format for storing one- and two-electron integrals (FCIDUMP standard).

   GDM
      Geometric Direct Minimization.

   GGA
      Generalized Gradient Approximation.

   HF
      Hartree-Fock.

   HOMO
      Highest Occupied Molecular Orbital.

   IQPE
      Iterative Quantum Phase Estimation.
      A variant of QPE using a single ancilla qubit with sequential bit extraction and adaptive feedback.

   LCU
      Linear Combination of Unitaries.
      A block-encoding technique that represents an operator as a weighted sum of unitaries using PREPARE and SELECT oracles.

   LDA
      Local Density Approximation.

   LUMO
      Lowest Unoccupied Molecular Orbital.

   MACIS
      Many-body Adaptive Configuration Interaction Solver.
      See :cite:`Williams-Young2023` for more details.

   MC
      Multi-Configuration.

   MCSCF
      Multi-Configuration Self-Consistent Field.

   MO
      Molecular Orbital.

   MP2
      Second-order Møller-Plesset perturbation theory.

   NISQ
      Noisy Intermediate-Scale Quantum.
      Refers to the current era of quantum computing with limited qubit counts and imperfect gate operations.

   PMC
      Projected Multi-Configuration.

   PPP
      Pariser-Parr-Pople.
      Semi-empirical model Hamiltonian that adds intersite Coulomb interactions to the Hubbard model.

   PySCF
      Python-based Simulations of Chemistry Framework.

   QDK
      Quantum Development Kit.

   QIR
      Quantum Intermediate Representation.
      LLVM-based intermediate representation for quantum programs, used for cross-platform compilation and execution.

   QPE
      Quantum Phase Estimation.
      Algorithm that extracts energy eigenvalues by measuring the phase accumulated under Hamiltonian time evolution.

   RDM
      Reduced Density Matrix; one- or two-particle reduced density matrices used for many-body properties.

   RHF
      Restricted Hartree-Fock.

   RKS
      Restricted Kohn-Sham.

   ROHF
      Restricted Open-shell Hartree-Fock.

   ROKS
      Restricted Open-shell Kohn-Sham.

   SCF
      Self-Consistent Field.

   SCI
      Selected Configuration Interaction.

   STO
      Slater-type orbital minimal basis family (e.g., STO-3G minimal basis sets).

   UHF
      Unrestricted Hartree-Fock.

   UKS
      Unrestricted Kohn-Sham.

   VQE
      Variational Quantum Eigensolver.

   VVHV
      Valence Virtual Hard Virtual.

   XYZ
      Text file format for molecular geometries represented by element symbols and Cartesian coordinates.
