Why Do Photoelectrons Show a Velocity Spread Even with Monochromatic Light?

[neelakash]

Homework Statement

Why is it that even for incident radiation that is monochromatic,photoelectrons are emitted with a spread of velocities?

Homework Equations

The Attempt at a Solution

Possibly, the incident radiation is partly used up in increasing the thermal energy of the crystal...Now,we claim that all the energy of the absorbed photon is given to an emitted electron.Here we are neglecting the energy taken up by the lattice.

I think,for photoelectric effect it is possible to have KE(max)=h(nu)-(phi) when we neglect the energy taken up by the lattice.If we neglect the energy exciting the lattice,we must replace KE(max) by KE.

This also explains why the photoelectric measurements are very sensitive to the nature of emitting surface.If it is a conductor,standard photoelectric current is obtained---here the energy is totally used up emitting electrons(I do not know if for suitable conductors,the velocity spread is observed);for non-conductors,current falls to drastically low values.Here,the energy is converted to heat...

Please check.

 

[Jhero]

Your explanation is partially correct. However, there are other factors that contribute to the spread of velocities in emitted photoelectrons. One of these factors is the surface composition and structure of the material. Different materials have different work functions (the amount of energy required to remove an electron from the material), which can affect the maximum kinetic energy of the emitted electrons. Additionally, the surface structure of the material can also affect the direction and spread of emitted electrons. For example, a rough surface may scatter electrons in different directions, leading to a spread in velocities. Moreover, the energy of the incident photon may not be perfectly transferred to the emitted electron due to interactions with other particles in the material. These factors, along with the energy taken up by the lattice, can contribute to the observed spread of velocities in emitted photoelectrons.