| Acronym | Meaning |
| BAT | Best Available Technology |
| 2PH TDA | Two-particle-hole Tamm-Dancoff Approximation (for Closed-shell |
| SID | Surface Ionization Detector |
| PGHS | Prostaglandin H Synthase |
| MASER | Microwave Amplification By Stimulated Emission Of Radiation |
| ECNI | Electron Capture Negative Ionization |
| NLSLE | Nonlinear Schroedinger-Langevin Equation |
| NMMAPS II | The National Morbidity |
| MC-MBPT | Multiconfiguration Many-body Perturbation Theory |
| TPPE | Two-photon Photoemission |