Autoionizing states are high-lying, electronically excited states of an atom or molecule that have sufficient energy to ionize. These states are typically short-lived and have a complex electronic structure due to the presence of highly excited electrons. Autoionizing states play a crucial role in phenomena such as photoionization, collisional ionization, and electron impact ionization. They are of particular interest in the field of atomic and molecular physics, as they provide valuable information about the electronic structure and dynamics of atoms and molecules. Researchers study autoionizing states using a variety of experimental and theoretical techniques to better understand their properties and behavior.