Excitation, ionization, TEMPERATURE?

In summary, when atomic electrons are excited or ionized, they contribute to a temperature rise. Energy of the electron is significant in this case, and it is related to the kinetic energy of the atom.
  • #1
huikhee
1
0
excitation, ionization, TEMPERATURE??

When atomic electrons are excited or ionized, do they contribute to temparature rise??
If yes, what energy of the electron is significant in this case??
 
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  • #2
what do u mean excited. Do u mean like passing a current through them?? Cause if that's what u mean, there is no temp change, only photon emmision.
 
  • #3
I'm guessing that it does, but thermo is not my strong point. If the atoms are excited, then they are more likely to emit higher frequency radiation (when they spontaneously decay). I would expect this to have an overall shifting effect of the peak of the radiation to a higher frequency, which means a higher temperature, if I'm not mistaken.
 
  • #4
Anyone know what the typical temperature in the ion tail of a comet is as it nears the Sun? Thanks.
 
  • #5
huikhee said:
When atomic electrons are excited or ionized, do they contribute to temparature rise??
Undoubtedly, yes.
huikhee said:
If yes, what energy of the electron is significant in this case??
I don't understand this part of the question. Could you elaborate further?

Claude.
 
Last edited:
  • #6
huikhee said:
When atomic electrons are excited or ionized, do they contribute to temparature rise??
If yes, what energy of the electron is significant in this case??

In a plasma, in which there are free electrons and ions/nuclei, one refers to ion and electron temperatures which are in equilibrium in the absence of external excitation. The temperature is related to the kinetic energy, and there is a distribution of temperature/kinetic energy. It doesn't make much sense to talk of a temperature of a bound electron, but rather temperature would be related to the kinetic energy of the atom.

For atoms in solids and liquids, the temperature is related to atomic vibrations.
 
  • #7
Astronuc said:
For atoms in solids and liquids, the temperature is related to atomic vibrations.

When you calculate the phonon heat capacity of a solid you assume that the electron contribution is negligible. I believe that this assumption is only viable in some substances. I am not sure whether this means that a substance at a given temperature may have fewer phonon exitacions than one would expect from a pure phonon model.
 
  • #8
"Temperature" as such is not really a well defined quantity in physics.One has be very specific about WHICH temperature one is referring to.
If you e.g. do electrical transport experiments at low temperatures the "electronic" temperature (the temperature you measure in an electrical measurement) is usually higher than the phonon temperature; and the difference can be quite significant.
The reason is simply that the electron-phonon interaction times become rather long at temperatures below about 100 mK. Hence, any "hot photons" that reach the device via the measurement leads will raise the temperatures of the electrons more than the temperature of the phonons.
Temperatures of about 200 mK or so are frequently seen even when the phonon temperature of the chip the device is fabricated on is at around 20 mK.

You can actually use the reversed effect as well. By using electronic cooling it is possible to lower the temperature of the electronos well below that of the phonons (the lattice)
 
  • #9
Atoms are excited and ionized all the time, even when everything is in thermal equilibrium. If they are, then the excitation and ionization obviously doesn't contribute to any change in temperature. The question actually isn't well posed.
 
  • #10
JeffKoch said:
Atoms are excited and ionized all the time, even when everything is in thermal equilibrium.
Good point, I assumed the excitation was due to external pumping, like one might find in a laser.

Claude.
 
  • #11
it should also be pointed out that at room temperature nearly everything will be in the ground state.
 

1. What is excitation?

Excitation is a process in which an atom or molecule gains energy, typically through the absorption of photons. This causes the electrons in the atom or molecule to move to higher energy levels, resulting in a temporary excited state.

2. What is ionization?

Ionization is the process of removing one or more electrons from an atom or molecule, resulting in the formation of a positively charged ion. This can occur through various means such as collisions with other particles or absorption of high energy radiation.

3. How does temperature affect excitation and ionization?

Temperature plays a crucial role in both excitation and ionization processes. As temperature increases, the average kinetic energy of particles also increases, leading to more frequent collisions and higher chances of excitation or ionization occurring.

4. What is the relationship between temperature and ionization energy?

Ionization energy is the minimum amount of energy required to remove an electron from an atom or molecule. This energy is directly proportional to temperature, meaning that as temperature increases, so does the ionization energy.

5. How are excitation and ionization related to plasma?

Plasma is a state of matter in which a significant portion of particles are ionized, meaning they have lost one or more electrons. This ionization can occur through excitation and is essential for the formation and maintenance of plasma.

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