Ångström

See also: Å

A ångström or angström (Symbole Å , or) is a unit of measurement in atomic Physique which does not belong to the international Système (IF). It is used for the wavelengths of the light known as “Nanométrique”. In astronomy, one says that the visible light is located between 4.000 and 7.500 Å roughly. There exist filters letting pass only a Wavelength specifies, like the filters Hα to approximately 6.563 Å.

1 ångström = 10 −10 Mètre = 0,1 Nanomètre = 100 Picomètre S. It should be specified that, the nanometer (noted Nm) is more used the ångström. A nanometer is equivalent to a billionth of meter, that is to say 10 −9 measure.

The ångström was named thus in the honor of the Physicien Swedish Anders Jonas Ångström, one of the inventors of the Spectroscopie. This unit is sometimes used to measure the dimension of Atome S which has a ray between 0,25 and 3 Å.

The old ångström (of which the symbol is Å* in order to distinguish it from the modern ångström) was defined starting from the Wavelength of the K-α-1 line of the Tungstène ; the latter was specified like being worth 0,209 010 exactly 0 Å*. Thus 1 Å*= 1,000 015 01×10 -10 ± 90×10 -18 Mr.

External bonds

Conversion of ångström towards other units of length

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