ae	all-electron
fc	frozen core
PES	potential energy surface
QFF	quartic force field
EDMS	electric dipole moment surface
CBS	complete basis set
CASSCF	complete active space self-consistent field
CCSD(T)	coupled-cluster with single, double, and perturbative triple excitations
CCSD(T*)-F12b	explicitly correlated coupled-cluster with single, double, and scaled perturbative triple excitations
CCSDT(Q)	coupled-cluster with single, double, triple and perturbative quadruple excitations
CCSDTQ	coupled-cluster with single, double, triple and quadruple excitations
CCSDTQP	coupled-cluster with single, double, triple, quadruple and pentuple excitations
ACPF	averaged coupled-pair functional
MRCI+D	multi-reference configuration interaction with singles and doubles including the Davidson correction
AQCC	averaged quadratic coupled-cluster
CV	core-core and core-valence correlation
SR	scalar-relativistic effects
HC	higher-order correlation
(Q)–(T)	difference between fc-CCSDT(Q) and fc-CCSD(T)
Q–(Q)	difference between fc-CCSDTQ and fc-CCSDT(Q)
P–Q	difference between fc-CCSDTQP and fc-CCSDTQ
DBOC	diagonal Born-Oppenheimer correction
VPT2	second-order vibrational perturbation theory
ZPVE	zero-point vibrational energy