(hydrogen lines for electrons settling from n > 2 to n = 2)
The Balmer series is the set of
hydrogen spectral lines emitted
when an electron descends from
an electron shell number n greater than 2 down to n = 2,
or the analogous absorption lines when absorbed electromagnetic radiation
makes the electron do the opposite.
It is one of the hydrogen line series, such as
the Lyman series and is
named after Johann Balmer.
- 3 -> 2: H-alpha, H-α, 656.3 nm (red)
- 4 -> 2: H-beta, H-β, 486.1 nm (cyan)
- 5 -> 2: H-gamma, H-γ, 434.1 nm (blue)
- 6 -> 2: H-delta, H-δ, 410.2 nm (violet)
- 7 -> 2: H-epsilon, H-ε, 397.0 nm (ultraviolet)
- 8 -> 2: H-zeta, H-ζ, 388.9 nm (ultraviolet)
- 9 -> 2: H-eta, H-η, 383.5 nm (ultraviolet)
- infinity -> 2: 364.6 nm (ultraviolet, the Balmer limit).
Formula for the wavelengths:
wavelength = Balmer's constant × n² / ( n²-4 )
- wavelength - within the Balmer series.
- Balmer's constant = 3.6450682 × 10-7 m or 364.50682 nm (same as 4/RH where RH is the Rydberg constant for hydrogen).
- n is the higher electron shell number.
The Balmer series, especially H-α is used
to determine the redshift of quasars and
distant galaxies because it is often prominent.
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Referenced by pages:
Balmer-break galaxy (BBG)
emission line galaxy (ELG)
HII region (HII)
Lyman series (L)
star formation rate (SFR)
shell star (sh)
spectral line energy distribution (SLED)
spectral line designation