| Acronym | Meaning |
| PEPECO | Photoelectron-photoelectron Coincidence |
| MOPA | Master Oscillator Power Amplifier |
| CN | Condensation Nucleus |
| CCSDTQP | CCSDTQ (and) Pentuple (excitations) |
| LUMO | Lowest Unoccupied Molecular Orbital |
| MP2(FC) | MP2(frozen Core) Only (outer) Valence Electrons Included In The Approximation |
| CCE | Counterflow Centrifugal Elutriation |
| TDLAS | Tunable Diode Laser Absorption Spectroscopy |
| HSA | Hyperspherical Adiabatic (for Resonances In Electron-atom Scattering. Energy Levels |
| WCRP | World Climate Research Programme |