| Acronym | Meaning |
| IVAP | Intimate Valence Alternation Pairs (bonding Model In Electronic Structure Calcns.) |
| CSI | Chemical Shift Imaging (NMR) |
| ERP | Emergency Response Planning |
| PNO | Pseudonatural Orbital |
| ODC | Optimized Double Configuration |
| OHER | Office Of Health And Environmental Research (US Dept. Of Energy) |
| HLG | Hedin-Lundqvist-Gunnarsson (spin D. Functional) |
| WHMO | Wolfsberg-Helmholz Molecular Orbital |
| SNIFTIRS | Subtractively Normalized Interfacial Fourier Transform IR Spectroscopy |
| HEN | High-efficiency Nebulizer |