 Inverse photoemission spectroscopy

Inverse photoemission spectroscopy (IPES) is a powerful experimental technique used to study the electronic states of materials, particularly surfaces and interfaces. In contrast to traditional photoemission spectroscopy (PES), which involves the excitation of electrons from a material by incident photons (measuring the emitted electrons), IPES involves the injection of electrons into a material, where these electrons can excite the material and subsequently emit photons.