# Can the kinetic energy of a photoelectron be greater than what's calculated by the photoelectric equation?

The photoelectric equation, which relates the energy of the incident photons to the maximum kinetic energy of the photoelectrons, is given as $E=h\upsilon -\phi$, where $h\upsilon$ represents the energy of the incident photon and $\phi$ represents the work function of the substance from which the photoelectrons are to be emitted.

My question: Is it possible for the photoelectrons to exchange energy among themselves by the means of Coulombic force? Or is the distance between them too large for the repulsive force to have a tangible effect on their respective energies?

The overall quantum yield is usually around $10^{-5}$ to $10^{-6}$ i.e. only one photon in one hundred thousand to a million ejects an electron from the metal, and that low yield is because the backscattering is so inefficient.