Higherlying

Higherlying is an adjective used in physics to describe energy states that lie above a chosen reference level, usually the ground state. In atomic and molecular systems, higher-lying states are excited states with discrete energy levels. Their populations depend on temperature, radiant input, or electronic excitation. Transitions between higher-lying and lower states emit photons with characteristic energies, forming spectral lines; absorption can raise systems from lower to higher states.

Near the ionization limit, many atoms exhibit a crowd of closely spaced higher-lying levels called Rydberg states, which show approximate hydrogenic scaling. These states are highly polarizable and can have large orbital radii, causing unique spectroscopic and dynamical properties.

In solids, higher-lying electronic states include excited bands above the valence band. Optical pumping can promote electrons to the conduction band, with relaxation processes returning population to lower-lying states and producing luminescence. In this context, higher-lying states also arise from excitons, defect levels, or surface states that participate in optical responses.

The term is relative and broad; higher-lying can refer to any level above a reference such as ground, a particular band, or a base energy. In spectroscopy and quantum dynamics, studying higher-lying states informs about interactions, lifetimes, transition probabilities, and selection rules.

See also: excited state; energy level; spectroscopy; Rydberg state; ionization.