Acronym definitions

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 [WYTMZdJ23] 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.