Photoelectron Spectroscopy

it is the way of analyzing the electronic structure of materials by measuring the kinetic energy of electrons emitted from a sample when it is irradiated with ultraviolet or X-ray light. This technique allows researchers to obtain information about the elemental composition, chemical state, and electronic configuration of the sample.

Those high-energy photons bombard a stream of atoms to remove all of their electrons.

Those electrons then get pushed away by a magnetic field, and land on a detector.

Those closer to the nucleus will require more energy from the photons to knock off, therefore, they would be shortest on the chart. But, outer electrons have the lowest electron-binding energy, making them easier to remove and resulting in a higher kinetic energy as they are emitted, which is reflected in their position further along the chart.

As you go from left to right in a period, the number of protons increases, thus the electronegativity increases. But as you go down a group, the distance between valence electrons and the nucleus increases, leading to a decrease in electronegativity. This is due to the additional electron shells, which shield the valence electrons from the nuclear charge, making it easier for these outer electrons to be removed. So, on a photoelectron spectrum, each spike would be further to the right.

BE = hv - KE [subscript] electron

BE = binding energy

hv = energy of the photon used to eject the electron, where h is Planck's constant. (or is the incident radiation.)

the energy needed to eject an electron from a sample is the electron’s ionization energy or binding energy.