What element with a high vapor point the emits to least light or radiation when heated to its vapor pressure point in a vacuum?

Ideally I would like to know in 0 gravity and 0 pressure which elements can be get the hottest around the sun before the vapor pressure point is reached and/or emit the least black body radiation when hot.


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    $\begingroup$ The black body radiation from all elements and compounds is the same. $\endgroup$ – Karl Apr 12 '19 at 20:33
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    $\begingroup$ i suppose an isolated proton wouldn't $\endgroup$ – A.K. Apr 13 '19 at 4:00
  • $\begingroup$ As for A.K. comment: your question should be what ensemble of matter does not emit EM radiation (or Vis, depending on your exact meaning) when hot? Then the answer is in the comment by Karl. (Dark matter not considered as for no chemistry can be done ;) $\endgroup$ – Alchimista Apr 13 '19 at 8:28
  • $\begingroup$ @Alchimista is this better? $\endgroup$ – Muze Apr 13 '19 at 15:52
  • $\begingroup$ Say substance, so you get rid of the fact that atoms/molecules can't have a T and a vapour pressure. Hot atoms are at best moving faster. But you got an answer so.... Referring to a limit made the Q interesting. $\endgroup$ – Alchimista Apr 14 '19 at 7:20

Technically, a smooth or molten, unoxidized metal surface (regardless of chemistry) makes a good candidate. This thesis from Auburn University reports the emissivities of both oxidized and unoxidized metals at temperatures typically encountered in industrial processes; note the low values for all the unoxidized metals studied in the IR range where most radiation is given off.

  • $\begingroup$ Yes but mecury has a low evaporation point. $\endgroup$ – Muze Apr 13 '19 at 19:10
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    $\begingroup$ @Muze — But the state does not matter in emitting electromagnetic waves! $\endgroup$ – SteffX Jul 10 '19 at 15:57
  • $\begingroup$ @Steffi can you please explain more in an answer for a Layman like myself can understand. $\endgroup$ – Muze Jul 10 '19 at 21:28
  • $\begingroup$ Will anyone please tell me what is wrong with this answer? $\endgroup$ – Oscar Lanzi Jul 10 '19 at 23:27
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    $\begingroup$ I thought maybe @SteffX would have went more into detail with an answer but he didn't. I think your answer is good. Tks $\endgroup$ – Muze Jul 12 '19 at 13:18

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