Is there way to thermalize an electron to room temperature?

In summary, at room temperature, the particle energy is 0.025eV which is the same for both neutron and electron. However, it is practically impossible to cool down a free electron to this low velocity, while bound electrons do not have a well-defined speed. In absolute 0K temperature, the atom orbital electrons do not become standstill, but rather follow the Fermi-Dirac statistics and have an expectation value for the kinetic energy. Free thermal electrons exist in metals, where some have zero kinetic energy while others have more. The electrons in a metal follow the Fermi-Dirac statistics rather than the classical Maxwell-Boltzmann statistics. Similarly, neutrons also follow the same statistics and do not significantly contribute to
  • #1
kiwaho
72
1
At room temperature, particle energy is 0.025eV.
Neutron capture reaction has big cross section when neutron is in room temperature. Theoretically, so does an electron. At 0.025eV, the electron velocity should be only 93.78km/s.
Unfortunately almost no way to cool down an free electron to so low velocity, even an outermost orbital electron of atom runs at least 1000km/s above, e.g. 2190km/s for hydrogen electron.
In absolute 0K temperature, do the atom orbital electrons no longer move and become standstill?
 
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  • #2
Bound electrons do not have a well-defined speed, this is independent of the temperature of the material. They have an expectation value for the kinetic energy, which is above 1/40 eV in most (but not all) cases, but this is not related to a temperature.

Free thermal electrons exist (just heat a metal wire), and in metals you have "free" (only constrained to the metal) electrons with (nearly) zero kinetic energy.
 
  • #3
mfb said:
Bound electrons do not have a well-defined speed, this is independent of the temperature of the material. They have an expectation value for the kinetic energy, which is above 1/40 eV in most (but not all) cases, but this is not related to a temperature.

Free thermal electrons exist (just heat a metal wire), and in metals you have "free" (only constrained to the metal) electrons with (nearly) zero kinetic energy.
Are you sure the "free" electron in metal has zero momentum? I don't think so.
 
  • #4
In absolute 0K temperature, do the atom orbital electrons no longer move and become standstill?
No. The electrons would be at the lowest state permitted by Pauli exclusion.
 
  • #5
kiwaho said:
Are you sure the "free" electron in metal has zero momentum? I don't think so.
Some of them do. Others have more.

The states start at zero kinetic energy, and get filled until all electrons have some state. The highest filled states are typically at kinetic energies way above thermal energies, but there are lower states as well.
 
  • #6
mfb said:
Some of them do. Others have more.

The states start at zero kinetic energy, and get filled until all electrons have some state. The highest filled states are typically at kinetic energies way above thermal energies, but there are lower states as well.
So, it sounds they obey Boltzman distribution. I see. thank you!
 
  • #7
They do not, they follow the Fermi-Dirac statistics, where the actual energy distribution is given by the density of states in the metal which depends on its crystal structure.
 
  • #8
Sure, electrons in your room are thermalized to room temperature.
 
  • #9
If a proton or positive ion appears nearby an "standstill" free electron, of course, the electron will begin to run to embrace the proton or ion, but it never falls bluntly onto proton or ion, instead be bound to orbit. I think that is because the electron is accelerated too far above room temperature, e.g. 13.6eV or more.
If we could exert a pull back force to counteract the electric suck force while they are meeting together, then it would be possible to see the electron slowly landing on the nucleus surface without having to be bound to orbit, and then see nuclear transmutation (electron capture beta decay).
 
  • #10
kiwaho said:
So, it sounds they obey Boltzman distribution. I see. thank you!
In fact, the electrons in a metal are one of the first examples in history of statistical mechanics, where Fermi-Dirac statistics rather than classical Maxwell-Boltzmann statistics must be applied. It solved the long-standing puzzle why the electrons do not significantly contribute to the specific heat of metals at room temperature. It saved the otherwise successful Drude theory of electric and heat conductivity. This discovery is due to Sommerfeld.
 
  • #11
vanhees71 said:
In fact, the electrons in a metal are one of the first examples in history of statistical mechanics, where Fermi-Dirac statistics rather than classical Maxwell-Boltzmann statistics must be applied. It solved the long-standing puzzle why the electrons do not significantly contribute to the specific heat of metals at room temperature. It saved the otherwise successful Drude theory of electric and heat conductivity. This discovery is due to Sommerfeld.
Neutron is Fermion too, so it should also obey the same statistics, and it will not significantly contribute to the specific heat of the metal U-235 of a fissile fuel.
But the fact is that all neutrons can precisely be thermalized to 0.025eV without an obvious distribution, as well as the specific heat is affected.
 
  • #12
kiwaho said:
If we could exert a pull back force to counteract the electric suck force while they are meeting together, then it would be possible to see the electron slowly landing on the nucleus surface without having to be bound to orbit, and then see nuclear transmutation (electron capture beta decay).
No, that does not work. Electrons are not classical particles.
kiwaho said:
Neutron is Fermion too, so it should also obey the same statistics, and it will not significantly contribute to the specific heat of the metal U-235 of a fissile fuel.
There are not enough free neutrons to fill any relevant fraction of the available states.
 

1. Can an electron be thermalized to room temperature?

Yes, it is possible to thermalize an electron to room temperature. Thermalization refers to the process by which an electron or a group of electrons reach thermal equilibrium with their surroundings, meaning they have the same temperature as their surrounding environment.

2. How is an electron thermalized to room temperature?

An electron can be thermalized to room temperature through collisions with other particles, such as atoms or molecules, in its surrounding environment. These collisions cause the electron to gain or lose energy until it reaches the same temperature as its surroundings.

3. What are the factors that affect electron thermalization?

The factors that affect electron thermalization include the type of material the electron is in, the density of the material, and the temperature and energy of the surrounding environment. Additionally, the energy and temperature of the electron itself can also impact the thermalization process.

4. Is there a limit to how much an electron can be thermalized?

Yes, there is a limit to how much an electron can be thermalized. This limit is determined by the temperature of its surrounding environment. Once the electron reaches thermal equilibrium with its surroundings, it cannot be further thermalized.

5. Why is thermalization important for studying electrons?

Thermalization is important for studying electrons because it helps us understand how they interact with their surroundings and how they behave in different environments. It is also crucial for technologies such as thermoelectric devices, which rely on the thermalization of electrons to convert heat into electricity.

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