Ionized Helium

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Excitation of the hyperfine transitions of atomic hydrogen, deuterium, and ionized helium 3 by Lyman-alpha radiation

  1. Ionization Energy Helium

Singly Ionized Helium Definition Singly ionized helium is an atom with one of its electrons missing. Assume that the remaining electron would behave like an electron of hydrogen. There is only one distinction between an atom of hydrogen and a single ionized atom of helium; the number of protons in the nucleus, hence the nuclear charge. (a) A singly ionized helium atom is in its n = 3 excited state, and then relaxes to its ground state by releasing a photon. What is the wavelength of the photon released in the relaxation process? (b) Read through section 6.4 of the textbook again, particularly the section labeled 'Electron Orbita'. Relatively few absorption lines. Lines of ionized helium and other lines of highly ionized atoms. Hydrogen lines appear only weakly. Peak of light in UV part of spectrum. Naos: B: Bluish-white: 10,000-30,000: Lines of neutral helium. Hydrogen lines more pronounced than in O-type stars. He I lines strong, as well as C II, O II, Si III. Excitation of the hyperfine transitions of atomic hydrogen, deuterium, and ionized helium 3 by Lyman-alpha radiation Deguchi, S.; Watson, W. The profile of Lyman-alpha radiation in an expanding gas cloud is calculated in detail in order to determine the color temperature of the radiation scattered by an H I atom within the cloud.

Abstract

The profile of Lyman-alpha radiation in an expanding gas cloud is calculated in detail in order to determine the color temperature of the radiation scattered by an H I atom within the cloud. Scattering of Ly╬▒ is likely to dominate in the excitation of the 21 cm transition of H I in astronomical gas clouds with very low densities. The spin temperature will then become equal to this color temperature. The method involves a Sobolov-like treatment and the application of a redistribution function for the scattering that preserves detailed balance when the recoil of the atom is included. Analogous color temperatures are calculated that are relevant for the excitation of the hyperfine transitions of atomic deuterium and ionized 3He.


Publication:
Pub Date:
First ionization energy of heliumIonized
March 1985
DOI:
10.1086/163014
Bibcode:
1985ApJ...290..578D
Keywords:

Ionization Energy Helium

  • Atomic Excitations;
  • Electron Transitions;
  • Helium Ions;
  • Hydrogen Atoms;
  • Hyperfine Structure;
  • Lyman Alpha Radiation;
  • Nebulae;
  • Centimeter Waves;
  • Computational Astrophysics;
  • Deuterium;
  • Helium Isotopes;
  • Hydrogen Clouds;
  • Radiative Transfer;
  • Radio Sources (Astronomy);
  • Scattering Functions;
  • Astrophysics