Talk:Einstein (unit)

No one uses this unit, because it is both poorly defined and redundant
People keep editing this article in ways that suggest that this unit is in use or even acceptable. Other than a few people who are apparently unaware of the problems with this unit, no one uses it in any field. It hasn't been acceptable for more than 40 years. The fact that it isn't used is strongly evident from its fast decline in publications: https://books.google.com/ngrams/graph?content=microeinstein&year_start=1800&year_end=2019&corpus=en-2019&smoothing=3.

It isn't well defined. There is no consensus. It isn't used. It isn't acceptable. Please stop making changes that suggest otherwise. 140.141.192.46 (talk) 02:30, 23 March 2023 (UTC)


 * Hello,
 * I don't know about "acceptable," since that's subjective, but I can guarantee you that it's used, especially in the fields of atmospheric and aquatic chemistry. See this paper, for example: https://pubs.acs.org/doi/epdf/10.1021/acs.oprd.2c00079 . I'm new to Wikipedia, so I'm not going to just edit this article... but I'm not sure "obsolete" is an appropriate description. If some people think it should be obsolete, then maybe that could be a new subsection? I'm not familiar enough with Wikipedia's standards.
 * Sharpie 928 (talk) 15:32, 25 July 2023 (UTC)
 * Yep. The unit is widely used . Dondervogel 2 (talk) 09:31, 26 July 2023 (UTC)
 * Agreed; I've come to this article checking the unit μE mentioned in Toxin-antitoxin systems in estuarine Synechococcus strain CB0101 and their transcriptomic responses to environmental stressors (Marsan et al. 2017), and a quick look suggests it's commonly used around research into cyanobacteria and algae with a number of articles published 2018–2023. Physics definitely isn't my area of expertise so I can't say as to whether it should be obsolete and abandoned, but it's certainly used in research contexts. ETA: https://books.google.com/ngrams/graph?content=%CE%BCE&year_start=1800&year_end=2019&corpus=en-2019&smoothing=3 shows it's increased in use, with microEinsteins appearing to be the most common use for the unit μE according to a quick search Pseudomugil (talk) 02:47, 6 August 2023 (UTC)

Einstein's vs Planck's contributions
introduced the idea of light quanta, now called photons, in a 1905 paper. I was under the impression that Plank had introduced that idea. Einstein simply showed that Plank's theory of light quanta explained the photoelectric effect Nik42 (talk) 02:54, 21 October 2008 (UTC)
 * Yeah, but it's Planck. J IM ptalk·cont 11:20, 11 April 2009 (UTC)
 * Planck introduced the idea that the energy of thermal radiation was absorbed or emitted in discrete amounts, which he called quanta. Planck knew light to be a wave, so the idea of it consisting of quanta would have been absurd for him. It wasn't something Planck suggested. Bobathon71 (talk) 22:53, 1 May 2013 (UTC)

Not a standard unit
I struggled a bit to find any references to the einstein in the standards literature, to no avail. I think it may never have been in any standard, but rather existed as a “folklore” unit, but I am not really sure about that. Here is a page which calls the einstein “A unit used in photochemistry, mid-20th century”. Even better, it cites a reference for this: “The mole is sometimes given the special but unnecessary (see Section 3.4, page 18) name 'einstein' in the particular case that the specified elementary particle is a photon...” (M. L. McGlashan. Physico-Chemical Quantities and Units. The Grammar and Spelling of Physical Chemistry. London: The Royal Institute of Chemistry, 1968.

In summary, as it appears the unit is commonly used even today, the article is needed, but the non-standard status of the unit should be emphasised, along with a recommendation to use the mole instead. I am almost tempted to do the edit myself, but feel it is a bit outside my expertise. Hanche (talk) 13:47, 14 April 2012 (UTC)

It's mentions in "Albert Einstein: A biography" by Albrecht Folsing. Where he states, that the einstein is "the (frequency-dependent) energy of one mole of light quanta". It's not an SI unit, and this page has the definition incorrect. 128.174.127.111 (talk) 20:16, 30 October 2013 (UTC)

The oldest definition of the unit I can find treats it as a unit of energy (equivalent to joules), not amount of substance (equivalent to moles). Noyes and Leighton say "A quantity of radiant energy Nhv is sometimes called an einstein" (The photochemistry of gases, page 14). Treatment as equivalent with the mole is new.

Please stop removing the definition as a unit of energy. That is clearly an old, and likely the original, use.

In either case, it is not a useful unit.

128.174.126.83 (talk) 16:32, 14 October 2019 (UTC)

I was reading that this article belongs to the physics section, which I assume explains the conclusion of an Einstein not being a useful unit. In chemistry it is often very useful to have values per mole, suche as the molecular weight, or the Farady constant, hence also the energy of one mole photons can be of usefulness to us photochemists. I would very much encourage to move the article to the subject of chemistry and point out the importance of molar quantities.2001:1716:4615:FC90:10E9:F3BD:18AF:2D4D (talk) 17:35, 31 January 2022 (UTC)


 * Moles are a useful unit. Joules are a useful unit. This unit is not useful because (1) it has two definitions and (2) each of those definitions is redundant with one of moles or joules. Those are well-defined, standard units, which should be used instead. 130.126.255.118 (talk) 19:19, 22 March 2023 (UTC)