Region of the electromagnetic spectrum extending from about 100 nm to 400 nm. This region is divided into four sub-bands as follows:
| Vacuum Ultraviolet (VUV) | 100-200 nm |
| UV-C | 200-280 nm |
| UV-B | 280-315 nm |
| UV-A | 315-400 nm. |
Note:
The notation and the limits of the various regions are as recommended by the International Commission on Illumination (CIE), with the exception that in these recommendations the UV-C range is 100-280 nm, including thus the vacuum UV range.
Source:
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 437 (https://doi.org/10.1351/pac200779030293)