| Subscript | Representation |
| 1D | One-dimensional |
| ad | Adsorbed |
| b | bulk |
| D | Diffusion |
| H | Atomic hydrogen |
| H2 | Molecular hydrogen |
| p | Permeate |
| r | Retentate |
| S | Solution |
| s | Surface |
| 0 | Reference |
| + | Forward |
| − | Backward |
| ‡ | Transition state |
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.