Term: low-pressure mercury lamp (arc)
https://doi.org/10.1351/goldbook.L03637

Definition:
resonance lamp that contains mercury vapour at pressures of about 0.1 Pa (0.75 x 10E-3 Torr; 1 Torr = 133.33 Pa). At 25°C, such a lamp emits mainly at 253.7 and 184.9 nm. They are also called germicidal lamps. There are cold- and hot-cathode as well as cooled electrode-less (excited by microwaves) low-pressure mercury lamps. The Wood lamp is a low-pressure mercury arc with an added fluorescent layer that emits in the UV-A spectral region (315-400 nm).

Related Terms:
1) resonance lamp (http://doi.org/10.1351/goldbook.R05339).
2) lamp (http://doi.org/10.1351/goldbook.L03447).
3) cathode (http://doi.org/10.1351/goldbook.C00905).
4) wood lamp (http://doi.org/10.1351/goldbook.W06682).

Source: PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 358 (https://doi.org/10.1351/pac200779030293)

Citation: 'low-pressure mercury lamp (arc)' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.L03637

License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms.

Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.