Question

What determines the height (or intensity) of each peak in a photoelectron spectrum?

Short answer

The height or intensity of each peak in a photoelectron spectrum is primarily determined by the number of electrons present in a specific energy state and the probability of those electrons transitioning when the material is irradiated with photons.

Step-by-step solution

Understanding Photoelectron Spectroscopy

Photoelectron spectroscopy is a technique in which photons (light particles) are shone onto a sample, causing it to emit photoelectrons. A spectrum is produced from the energies of the photoelectrons. The position of the peaks in this spectrum corresponds to the binding energy of the electrons in the sample, while the height or intensity of the peaks corresponds to the number of photoelectrons detected with a particular energy.

Understand the Concept of the Photoelectric Effect

The photoelectric effect explains how electrons are ejected from the surface of a material (in this case, the sample) when it absorbs light (photons). The energy of the incident photon needs to be greater than the binding energy of the electron in its orbit for the electron to be emitted. If this condition is met, a photoelectron is produced.

Know the Factors Influencing the Intensity of Peaks

The height or intensity of each peak in a photoelectron spectrum is determined mainly by two factors: the number of electrons present in a specific energy state and the probability of a transition occurring from this state when the material is irradiated with photons. The greater the number of electrons in a particular state, and the higher the transition probability, the taller the peak will be in the spectrum.