Abbreviations and Acronyms

1D one-dimensional AA Aharonov-Anandan ADMR absorption-detected magnetic resonance ADP adenosine diphosphate AFC automatic frequency control AFM atomic force microscopy AFP adiabatic fast passage AILFT ab initio ligand-field theory AO atomic orbital AOM angular overlap model ARS Advanced Research Systems ATP adenosine triphosphate AWG arbitrary waveform generator BDPA a,ß-bisphenylene-ß-phenylallyl-benzolate BEBOP broadband excitation by optimized pulses BIR4 $B_1$ insensitive rotation BO Born-Oppenheimer BP Breit-Pauli BPP Bloembergen, Purcell, Pound BW bandwidth BWO backward-wave oscillator C-NOT controlled-NOT C-PHASE controlled-phase CAP constant adiabaticity pulse CASPT2 complete active space second-order perturbation theory CASSCF complete active space self-consistent field CC coupled cluster CESR conduction electron-spin resonance CFT crystal field theory CIDEP chemically induced dynamic electron polarization CIDME chirp-induced dipolar modulation enhancement CLR cross-loop resonator CP combination-peak CPMG Carr-Purcell-Meiboom-Gill CPT coherence pathway transfer CSR coherent synchrotron radiation CT clock transitions CT coherence transfer CW continuous wave DAC digital-to-analog converter DC direct current DD dynamical decoupling DDBSQ 2,5-dichloro-3,6-dihydroxy-1,4-benzosemiquinone DDS direct digital synthesizer DEER double electron-electron resonance DEER ESE deadtime-free ESEEM by nuclear coherence-transfer echoes DFDMR delayed fluorescence detection of magnetic resonance DFG Deutsche Forschungsgemeinschaft DFT density functional theory DKH Douglas-Kroll-Hess DNP dynamic nuclear polarization DONUT double nuclear coherence transfer DPPH 2,2-diphenyl-1-picrylhydrazyl DQ double-quantum DQC double-quantum coherence DQF DQ filtering DQM double-quantum modulation DSV diameter spherical volume EC electron coherence ED-EPR echo-detected EPR EDDEER electrically detected double electron-electron resonance EDMR electrically detected magnetic resonance EFG electric field gradient EIK extended interaction klystron EIO extended interaction oscillator ELDOR electron-electron double resonance ELDOR-detected NMR electon-nuclear double resonance EP electron polarization EPR electron paramagnetic resonance EPRI EPR imaging EPRM EPR microscopy ESE electron spin echo ESEEM electron spin echo envelope modulation ET electron transfer EZ electron Zeeman f.w.h.h. flavin adenine dinucleotide FBP filtered backprojection FD-EPR frequency-domain EPR FD-FT THz-EPR fluorescence detection of magnetic resonance FDMR frequency-domain magnetic resonance FEL free-electron laser FFT fast Fourier transformation FID free induction decay FJ field-jump FMR ferromagnetic resonance FPGA field-programmable gate array FR Faraday rotator FRET fluorescence resonance energy transfer FT Fourier transform FT Fourier transformation FWHM full width at half maximum GGA generalized gradient approximation GIAOs gauge-including atomic orbitals GM Gifford-McMahon HAS hindered amine stabilizers HF Hartree-Fock HF high magnetic field HF hyperfine HFCs hyperfine couplings HFEPR high-frequency and high-field EPR HFHF high-field high-frequency HFI hyperfine interaction HFML High Field Magnet Laboratory HOMO highest occupied molecular orbital HS high-spin HTA high-turning-angle HWHH half width at half height hwhm half-width at half maximum HYSCORE hyperfine sublevel correlation ID instantaneous diffusion IF intermediate frequency INS inelastic neutron scattering IQ in-phase quadrature IRESE inversion recovery electron spin-echo ISC intersystem crossing ISHE inverse spin Hall effect JB Jeener-Broekaert KS Kohn-Sham KSM Kaplan, Solomon, and Mott LAC level anticrossing LAN local area network LCP left circular polarization LDA ``local density'' approximation LF-DFT ligand-field density functional theory LFT ligand-field theory LGR loop-gap resonator LHS left-hand side LiPc lithium phthalocyanine LMO localized molecular orbital LNA low-noise amplifier LO local oscillator LP lone-pair LUMO lowest unoccupied molecular orbital LWHH linewidth at half height MCD magnetic circular...