Spectrum is a concept introduced by Isaac Newton in the seventeenth century, denoting the totality of all values of a physical quantity. Energy, mass, optical radiation. It is the latter that is often meant when we talk about the spectrum of light. Specifically, the spectrum of light is a collection of bands of optical radiation of different frequencies, some of which we can see every day in the outside world, while some of them are inaccessible to the naked eye. Depending on the possibility of perception by the human eye, the spectrum of light is divided into the visible part and the invisible part. The latter, in turn, to infrared and ultraviolet light.
Types of spectra
There are also different types of spectra. There are three of them, depending on the spectral density of the radiation intensity. Spectra can be continuous, line and striped. The types of spectra are determined using spectral analysis.
Continuous spectrum
A continuous spectrum is formed by high-temperature solids or high-density gases. The well-known rainbow of seven colors is a direct example of a continuous spectrum.
Linedspectrum
The line spectrum also represents the types of spectra and comes from any substance that is in the gaseous atomic state. It is important to note here that it is in the atomic, not the molecular. Such a spectrum provides an extremely low interaction of atoms with each other. Since there is no interaction, the atoms emit waves of the same wavelength permanently. An example of such a spectrum is the glow of gases heated to a high temperature.
Striped spectrum
The striped spectrum visually represents separate bands, clearly delimited by rather dark intervals. Moreover, each of these bands is not the radiation of a strictly defined frequency, but consists of a large number of closely spaced light lines. An example of such spectra, as in the case of the line spectrum, is the glow of vapors at high temperatures. However, they are no longer created by atoms, but by molecules that have an extremely close common bond, which causes such a glow.
Absorption spectrum
However, the types of spectra still do not end there. Additionally, another type is distinguished, such as an absorption spectrum. In spectral analysis, the absorption spectrum is dark lines against the background of a continuous spectrum and, in essence, the absorption spectrum is an expression of the dependence of the wavelength on the absorption index of the substance, which can be more or less high.
Although there is a wide range of experimental approaches to measuring absorption spectra. MostA common experiment is when the generated beam of white light radiation is passed through a cooled (for the absence of particle interaction and, consequently, luminescence) gas, after which the intensity of the radiation passing through it is determined. The transferred energy could well be used to calculate absorption.
