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photon79
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In free electron theory, electron doesn't feel any potential due to ions r co-electronsm they r totally free..then why don't they fly off from the metal boundaries?
photon79 said:In free electron theory, electron doesn't feel any potential due to ions r co-electronsm they r totally free..then why don't they fly off from the metal boundaries?
Gokul43201 said:A little further down in your study, you'll see the the idea of a sample boundary is conveniently done away with by imposing a (periodic) boundary condition that treats the sample as if it were devoid of boundaries.
Coming back to original question, the reason that the electron doesn't fly off the boundary can be separately explained in terms of a large boundary potential, known as the work function. However, the theory does not worry about the effect of this potential on the interior electrons, as they are sufficiently far away from it. The number of electrons "near" the surface, at any point of time is neglected with respect to the total number of electrons. This is not a bad approximation to make.
Modey3 said:A little off topic, doesn't the basis of thermionic emission involve electrons hopping off the boundaries when the material is heated ?
Modey3
The Free Electron Theory is a scientific theory that explains the behavior of electrons in solid materials. It proposes that electrons in metals are not bound to specific atoms, but instead are free to move throughout the material.
The theory states that the free electrons in metals are responsible for the material's ability to conduct electricity. When a voltage is applied, the free electrons move in response to the electric field, creating a flow of current.
While the theory is useful for explaining the behavior of electrons in metals, it does not account for the behavior of electrons in non-metallic materials such as insulators. It also does not explain the effects of temperature on electron behavior.
The Free Electron Theory laid the foundation for our understanding of electronic properties in materials. It has led to advancements in technology, particularly in the fields of electronics and semiconductors.
The theory has undergone several revisions and modifications since its initial proposal in the early 20th century. Some of these modifications include the inclusion of quantum mechanical principles and the concept of band theory to better explain the behavior of electrons in materials.