Talk:Volta potential

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Fermi level vs electrochemical potential

The article is not correct. "A voltmeter does not measure vacuum electrostatic potentials, but instead the difference in Fermi level between the two materials, a difference that is exactly zero at equilibrium."

A voltmeter measures the electrochemical potential difference across the measured sample. At equillibrium this is zero. However, the chemical potential (the fermi level is chemical potential at T=0) is distinct from one material to another.

See the classic article, "What does a voltmeter measure?" by Dr. Ilan Riess http://phstudy.technion.ac.il/~sp118028/SSI%20(1997)%20What%20does%20a%20voltmeter%20measure.pdf — Preceding unsigned comment added by 131.215.51.229 (talk) 00:13, 16 May 2013 (UTC)[reply]

Hi, thanks for the comment. I agree except about the definition of Fermi level. You've touched on one of the nomenclature problems that exists solid state physics and electrochemistry these days. Basically, Fermi level is not the same thing as Fermi energy. The former is usually defined as completely equivalent to electrochemical potential for electrons (i.e. total chemical potential), whereas the latter is usually defined only at absolute zero as the chemical potential for electrons minus some potential energy (i.e. internal chemical potential). Also Fermi level seems to only used to describe electrons, while the term Fermi energy is also used for Fermi gases other than electrons (e.g. neutron stars). Unfortunately these definitions aren't totally universal [1] [2]. Even more unfortunately, the definition of "electrochemical potential" and "chemical potential" aren't universal either [3]. So, all in all a bit of a headache to write for.--Nanite (talk) 20:07, 17 May 2013 (UTC)[reply]

(by the way, thanks for the reference, it's nice and concise; I added it to the Fermi level page). — Preceding unsigned comment added by Nanite (talk • contribs) 20:35, 17 May 2013 (UTC)[reply]

Confusion

This article is incorrect. It confuses the Galvani potential with the Volta potential. It would be better for the current content to be deleted than for it to continue to exist and give wrong information.— Preceding unsigned comment added by 70.180.229.84 (talk • contribs) 18:46 28 June 2014