"In atomic physics, the **fine structure** describes the splitting of the spectral lines of atoms due to first order relativistic corrections.

"The gross structure of line spectra is the line spectra predicted by non-relativistic electrons with no spin. For a hydrogenic atom, the gross structure energy levels only depend on the principal quantum number *n*. However, a more accurate model takes into account relativistic and spin effects, which break the degeneracy of the energy levels and split the spectral lines. The scale of the **fine structure** splitting relative to the gross structure splitting is on the order of (ZÎ±)^{2}, where Z is the atomic number and Î± is the fine-structure constant, a dimensionless number equal to approximately 7.297Ã—10^{âˆ’3}.

"The **fine structure** can be separated into three corrective terms: the kinetic energy term, the spin-orbit term, and the Darwinian term." Wikipedia, Fine Structure

See Also

**Chord**
**Fine Structure Constant**
**Fraunhofer Lines**
**Hyperfine Structure**
**Signature**
**Silent Sound Spread Spectrum**
**Spectra**
**Spectroscopy**
**Spectrum**
**Wavefunction**