What is spectrum chemistry

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The electromagnetic spectrum and its spectral ranges

The electromagnetic radiation classified according to its wavelength or frequency is called the electromagnetic spectrum. Originally, spectrum was only understood to mean the color band that is created when white light (e.g. sunlight) falls through a slit onto a prism or grating and is deflected to different degrees according to its different wavelengths. The entire electromagnetic spectrum, which extends from short-wave cosmic radiation to long-wave radio waves, covers more than 24 decades, which are divided into spectral ranges for clarity.

Optical spectroscopy is understood to mean not only the spectral range between and (called visible light) that is sensitive to the human eye, but also the energetically lower infrared range and the higher energetic range of the ultraviolet.

We see all bodies that absorb or emit in the area between and in color.

The sensory impression white means that our eyes receive all wavelengths of the visible range. If we see a body black, it absorbs the electromagnetic radiation at least in the range between and.

A color impression only arises when the observed body absorbs certain wavelengths and only reflects or lets through the rest of the spectrum. Since each wavelength is assigned a color, in this case our eyes no longer see white, but the color of the residual light. Such color pairs are called complementary colors (e.g. red-turquoise, blue-yellow, green-violet). For example, white light shines on a body that absorbs red light, so the color impression of the light reflected by the body appears turquoise to our eyes.