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A demonstration of the 589 nm D 2 (left) and 590 nm D 1 (right) emission sodium D lines using a wick with salt water in a flame. The Fraunhofer C, F, G′, and h lines correspond to the alpha, beta, gamma, and delta lines of the Balmer series of emission lines of the hydrogen atom. The Fraunhofer letters are now rarely used for those lines.
A spectral line is a weaker or stronger region in an otherwise uniform and continuous spectrum. It may result from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.
The spectrum appears in a series of lines called the line spectrum. This line spectrum is called an atomic spectrum when it originates from an atom in elemental form. Each element has a different atomic spectrum. The production of line spectra by the atoms of an element indicate that an atom can radiate only a certain amount of energy.
The "visible" hydrogen emission spectrum lines in the Balmer series. H-alpha is the red line at the right. Four lines (counting from the right) are formally in the visible range. Lines five and six can be seen with the naked eye, but are considered to be ultraviolet as they have wavelengths less than 400 nm.
With the exception of flames and graphite furnaces, which are most commonly used for atomic absorption spectroscopy, most sources are used for atomic emission spectroscopy. Liquid-sampling sources include flames and sparks (atom source), inductively-coupled plasma (atom and ion source), graphite furnace (atom source), microwave plasma (atom and ...
The term principal came about because this series of lines is observed both in absorption and emission for alkali metal vapours. [2] Other series of lines appear in the emission spectrum only and not in the absorption spectrum, and were named the sharp series and the diffuse series based on the appearance of the lines. [3] [2]
ammonium ions any 2400–3200 multiple broad peaks C─O alcohols: primary 1040–1060 strong, broad secondary ~1100 strong tertiary 1150–1200 medium phenols any 1200 ethers aliphatic 1120 aromatic 1220–1260 carboxylic acids any 1250–1300 esters any 1100–1300 two bands (distinct from ketones, which do not possess a C─O bond) C─N
An atomic spectral line refers to emission and absorption events in a gas in which is the density of atoms in the upper-energy state for the line, and is the density of atoms in the lower-energy state for the line. The emission of atomic line radiation at frequency ν may be described by an emission coefficient with units of energy/(time × ...