Читать книгу Astrobiology - Charles S. Cockell - Страница 65

The hydrogen atom, which is of course a common constituent of the Universe, is a special case, since its mass number, the value of Z, is 1. This leads to the general formula for the energy required for an electron to change energy levels in this atom as:

(3.7)

The wavelength of light that would be emitted or taken up by a transition between these two energy levels is therefore also given by:

(3.8)

This equation can also be expressed in a different way, known as the Rydberg formula (for hydrogen):

(3.9)

where the Rydberg constant (R_∞) is equal to Ry/hc and has a value of 1.097 × 10⁷ m⁻¹.

A special case of this equation is when hydrogen is ionized. In this case, the electron is completely removed from the atom, so that n₂ = ∞. If the electron is in the ground state (i.e. n₁ = 1), then the energy required for ionization is equal to Ry eV or 13.6 eV.