Electron excitation is a general term for any interaction between a photon (particle of light) and an electron. It refers to the process where an electron in an atom or molecule gains energy and jumps to a higher energy level.
Electrons can be excited by various sources, such as:
- Photoexcitation: This specifically refers to the absorption of a photon by an electron, leading to the electron’s transition to a higher energy level. This excited state can have various consequences, depending on the system involved. For example, it can trigger chemical reactions, cause fluorescence, or lead to the emission of other photons.
- Collisional excitation: This occurs when an energetic particle (another electron, ion, etc.) collides with an electron, transferring some of its kinetic energy to the electron and promoting it to an excited state.
- Thermal excitation: When atoms or molecules vibrate due to heat, this energy can be transferred to their electrons, exciting them to higher energy levels. This plays a crucial role in many chemical reactions and physical phenomena.
- Chemical excitation: During chemical reactions, the rearrangement of electrons creates and breaks bonds, often resulting in excited states within the participating molecules.
- Impact excitation: In certain materials like semiconductors, bombarding the material with high-energy particles (e.g., electrons, ions) can directly excite electrons.
- Electrostatic excitation: Applying a strong electric field can create an external force on electrons, potentially pushing them to higher energy levels.
- Field ionization: In very strong electric fields, electrons can be ripped out of their atomic or molecular orbitals altogether, resulting in a highly excited state before reaching the vacuum level.