Emission of light from incandescence of metals

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Discussion Overview

The discussion focuses on the emission of electromagnetic radiation from metals when heated or subjected to electric current. Participants explore the underlying mechanisms, particularly in relation to band structure and the role of electrons, while also addressing classical descriptions of radiation emission and the concept of black body radiation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that the emission of EM radiation from metals can be fundamentally understood through band structure and the involvement of electrons.
  • Others argue that black body radiation is a relevant concept, linking it to the random kinetic motion of charged particles.
  • One participant suggests that all electrons and the nucleus are involved in the emission process, while questioning the relevance of band structure to black body radiation.
  • There is a contention regarding the classical description of radiation emission, with some believing it holds to some degree, while others challenge its applicability in this context.
  • Some participants assert that metals are excellent absorbers and reflectors of EM radiation, with varying emissivity depending on temperature, complicating the black body analogy.

Areas of Agreement / Disagreement

Participants express differing views on the role of band structure in black body radiation and the classical description of radiation emission. There is no consensus on the fundamental mechanisms involved in the emission of light from metals.

Contextual Notes

Participants highlight limitations in addressing specific aspects of the questions posed, indicating that some responses may not directly correspond to the original inquiries. The discussion reflects varying interpretations of the relationship between band structure, electron behavior, and radiation emission.

bentzy
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TL;DR
This upload regards two linked questions, as follows: a. what's the detailed mechanism explaining the emission of light from metal.
b. does the classical model of radiation due to decelaration of electrons hold here ?
c. references related to these 2 questions.
a. We know metals emit EM radiation upon heating or electric current. I'd like to understand more fundamentally how this phenomenon takes place, on the basis of the basis of band structure, and which electrons are involved ?
b. Classically, charges emit radiation when accelarating or decelarating. Why doesn't description hold here ? Also, what are the limiting conditions between the description, namely does each hold ?
c. It'll be very kind to get references dealing with these two descriptions, and the questions raised.
Thanks, BC
 
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The first stop is black body radiation. It can be understood as the radiated energy from random kinetic motion of charged particles as per b). Metals are excellent absorbers of EM radiation, and so tend to make very good black bodies, however the band structure of some metals e.g. gold can give them a coloured appearance due to the variation in absorption and reflection across the visible spectrum.
 
The issues mentioned in your answer are well known, and don't correspond to what asked. Answers should be relevant to the specific aspects & phenomena in question(s).
Thank you for trying.
BC
 
bentzy said:
a. We know metals emit EM radiation upon heating or electric current. I'd like to understand more fundamentally how this phenomenon takes place, on the basis of the basis of band structure, and which electrons are involved ?
I suspect all of the electrons are involved, as is the nucleus, since ions, and their corresponding bound electrons, vibrate in place and can move with vibrations and waves within the lattice. I don't think band structure has much to do with blackbody radiation, as a thermal spectrum isn't separated into discrete emission bands.

bentzy said:
b. Classically, charges emit radiation when accelarating or decelarating. Why doesn't description hold here ?
I believe it does to some degree, though I can't say how accurate such a description is.
 
bentzy said:
The issues mentioned in your answer are well known, and don't correspond to what asked. Answers should be relevant to the specific aspects & phenomena in question(s).
Thank you for trying.
BC
You asked about metals giving off light when they are heated. That's black body radiation. If it's not the answer you want, perhaps you should rephrase your question instead of being condescending.
 
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Claude Bile said:
b). Metals are excellent absorbers of EM radiation, and so tend to make very good black bodies, however the band structure of some metals e.g. gold can give them a coloured appearance due to the variation in absorption and reflection across the visible spectrum.
I wouldn't think so. Metals are good reflectors, at least near the visible range. Their emissivity is about 0.1 (near room temperature), which make them poor black bodies. They get closer to black bodies near their fusion point, but usually they are still far from it.
 

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