Lyman series

Lyman Series

The Lyman series refers to a series of spectral lines in the ultraviolet (UV) region of the electromagnetic spectrum. These lines are emitted when an electron in a hydrogen atom transitions from a higher energy level to the first energy level (n=1). The Lyman series is named after its discoverer, Theodore Lyman, an American physicist who first observed these lines in 1906.

History

The discovery of the Lyman series was a significant milestone in the understanding of atomic structure. Prior to Lyman's work, it was known that atoms emitted and absorbed light at specific wavelengths, but the underlying mechanism was not well understood. Lyman's experiments with hydrogen gas and a spectrometer allowed him to observe a series of distinct lines in the UV region, which could be explained by the transitions of electrons within the hydrogen atom.

Spectral Lines

The Lyman series consists of a sequence of spectral lines, each corresponding to a different transition of the electron in a hydrogen atom. The wavelengths of these lines can be calculated using the Rydberg formula:

1/λ = R * (1/n1^2 - 1/n2^2)

where λ is the wavelength of the emitted or absorbed light, R is the Rydberg constant, and n1 and n2 are the principal quantum numbers of the initial and final energy levels, respectively.

The Lyman series starts with the transition from the first excited state (n=2) to the ground state (n=1), resulting in the Lyman-alpha line. This line has a wavelength of approximately 121.6 nanometers (nm) and is the most prominent line in the series. Subsequent transitions produce the Lyman-beta line (102.6 nm), Lyman-gamma line (97.3 nm), and so on.

Significance

The Lyman series has played a crucial role in the field of astrophysics. By studying the absorption and emission spectra of distant celestial objects, astronomers can determine the presence of hydrogen and its properties. The Lyman series is particularly useful for studying the interstellar medium, as the UV radiation emitted by hot stars can be absorbed by hydrogen gas, leaving characteristic absorption lines in the spectrum.

Applications

The Lyman series has found applications in various scientific disciplines. In atomic physics, the series provides valuable insights into the energy levels and transitions of hydrogen atoms. It has also been used to study other elements and ions, as the energy levels of these systems can be approximated using the same principles.

In astrophysics, the Lyman series is used to analyze the composition and temperature of celestial objects. By measuring the intensity and position of the Lyman lines in a spectrum, astronomers can determine the redshift or blueshift of distant galaxies, which provides information about their motion relative to Earth.

References

1. Lyman, T. (1906). "The Spectrum of Hydrogen". Physical Review, 23(3), 289-297. 2. Drake, G. W. F. (2006). "The Lyman Series". Journal of the Royal Astronomical Society of Canada, 100(2), 84-86.

See Also

• Balmer series
• Paschen series
• Brackett series
• Pfund series