Excitationstillstånd

Excitationstillstånd, often translated as excited state, refers to a condition in an atom or molecule where one or more electrons are in a higher energy level than their ground state. In the ground state, electrons occupy the lowest available energy orbitals. When an atom or molecule absorbs energy, for instance from light or heat, an electron can jump to a higher energy orbital, thus entering an excited state. This absorption of energy is quantized, meaning only specific amounts of energy corresponding to the difference between energy levels can be absorbed.

An excited state is generally unstable. The electron will naturally tend to return to its ground state, or a lower energy level, by releasing the absorbed energy. This energy is often emitted as a photon of light, which is characteristic of the specific element or molecule. The color of light emitted depends on the energy difference between the excited state and the lower energy level to which the electron transitions. This phenomenon is fundamental to spectroscopy, where the emission and absorption spectra of substances are used for identification and analysis. Excited states can also return to lower energy states through non-radiative processes, such as collisions with other particles, where the energy is converted into kinetic energy. The lifetime of an excited state can vary significantly, from nanoseconds to much longer periods.