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Emission spectrum of a ceramic metal halide lamp. 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 emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to electrons making a ...
The classical example of a discrete spectrum (for which the term was first used) is the characteristic set of discrete spectral lines seen in the emission spectrum and absorption spectrum of isolated atoms of a chemical element, which only absorb and emit light at particular wavelengths. The technique of spectroscopy is based on this phenomenon.
An example is the emission spectrum of nebulae. [38] Rapidly moving electrons are most sharply accelerated when they encounter a region of force, so they are responsible for producing much of the highest frequency electromagnetic radiation observed in nature.
For example, the 2 → 1 line is called "Lyman-alpha" (Ly-α), while the 7 → 3 line is called "Paschen-delta" (Pa-δ). Energy level diagram of electrons in hydrogen atom. There are emission lines from hydrogen that fall outside of these series, such as the 21 cm line.
The hole, then, is a close approximation of a theoretical black body and, if the cavity is heated, the spectrum of the hole's radiation (that is, the amount of light emitted from the hole at each wavelength) will be continuous, and will depend only on the temperature and the fact that the walls are opaque and at least partly absorptive, but not ...
The "mass emission coefficient" j ν is equal to the radiance per unit volume of a small volume element divided by its mass (since, as for the mass absorption coefficient, the emission is proportional to the emitting mass) and has units of power⋅solid angle −1 ⋅frequency −1 ⋅density −1. Like the mass absorption coefficient, it too ...
The rule is relevant in understanding the emission spectrum of an excited molecule. Upon absorbing a photon, a molecule in its electronic ground state (denoted S 0, assuming a singlet state) may – depending on the photon wavelength – be excited to any of a set of higher electronic states (denoted S n where n>0).
This type of observation is called a dynamic spectrum, and much of the terminology used to describe solar radio emission relates to features observed in dynamic spectra, such as the classification of solar radio bursts. [8] Examples of dynamic spectra are shown below in the radio burst section.