The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an atom or molecule making a transition from a high energy state to a lower energy state
A second kind of emission spectrum results from fluorescence by excitation of X-rays, ultraviolet rays, cathode rays or visible radiation
Emission lines refer to the fact that glowing hot gas emits lines of light, whereas absorption lines refer to the tendency of cool atmospheric gas to absorb the same lines of light
2 shows examples of a continuous, an emission and an absorption spectrum
) Emission Spectra VS Absorption Spectra
According to the modern atomic theory, these electrons are positioned in specific energy levels called shells or orbitals where their energies are quantized
Excitation spectra are particularly useful in the following cases: 1
Note: Vysis SpectrumGreen™ products may be labeled with either SpectrumGreen1 or SpectrumGreen2 fluorophore
7 and 8
excitation to emission, is measured in only billionths of a second, the phenomenon is a stunning manifestation of the interaction between light and matter that forms the basis for the expansive fields of steady state and time-resolved fluorescence spectroscopy and microscopy
Excitation is equivalent to absorption since upon absorption, the molecule reaches the excited state S n
A gas of hydrogen atoms will produce an absorption line spectrum if it is between you (your telescope+spectrograph) and a continuum light source, and an emission line spectrum if viewed from a different angle
Light that consists of all visible colours (white light) is called a continuous spectrum
An example of how spectra (in this case, an emission line spectrum) are observed (NASA, ESA, and the Hubble SM4 ERO Team ) On the left side of the montage above is an image of Eta (η) Carinae, a binary star system in which the more massive star is ejecting mass at a tremendous rate (about one solar mass per millennium), and is within a million