Hydrogen emits light in frequency series {spectra, atomic} {atomic spectra} {line spectrum}.
series
Frequencies 82000 cm^-1 to 110000 cm^-1 {Lyman series} are ultraviolet and start from ground state in shell 1. Frequencies 15000 cm^-1 to 28000 cm^-1 {Balmer series} are visible and start from ground state in shell 2. Frequencies 5000 cm^-1 to 12500 cm^-1 {Paschen series} are infrared and start from ground state in shell 3. Frequencies {Brackett series} can start from ground state in shell 4. Frequencies {Pfund series} can start from ground state in shell 5.
Rydberg formula
Hydrogen spectra, and similar electron-transition energy series, are regular {Rydberg formula}.
cause
Heat energy can put electrons into higher orbitals. Materials emit electromagnetic radiation when electrons fall back to lower orbitals.
temperature
In low-density gas, temperature change changes intensities but not frequencies. Intensity E at frequency is proportional to temperature T to fourth power: E = k * T^4.
density
Dense matter emits continuous frequency spectrum, because molecules interact. Dense-matter spectra depend only on temperature, because temperature determines interactions.
radiation temperature
Light at definite wavelength has definite temperature, because light is kinetic energy. Radiation temperature depends on beam solid angle and intensity, as well as wavelength.
Elements absorb light frequencies {absorption spectra}|.
Absorption lines {Fraunhofer line} of Sun elements make absorption spectrum.
Elements emit light frequencies {emission spectra}|.
Moving charges in atoms make magnetic fields that split spectrum peaks {fine structure}| {fine spectra}. Bigger nuclei make bigger magnetic fields and so make larger fine structure. Spin-orbit coupling and Zeeman effect also contribute to fine structure.
5-Physics-Matter-Atom-Wavelength Change
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Date Modified: 2022.0225