Navigation Links
Absorption spectrum


An absorption spectrum is a diagram depicting the wavelengths of electromagnetic radiation absorbed by a material, usually a gas. It can be regarded as the opposite to an emission spectrum, which is a depiction of the specific wavelengths emitted by a material.

Let us consider white light, which consists of electromagnetic radiation at all frequencies, passing through a sample of cold gas. For any collection of atoms or molecules, there are certain specific amounts of energy required to change state; for individual atoms, these correspond to an electron moving from one orbit (energy level) to another. An electron can jump to a higher orbit if it is given the exact amount of energy by one single photon, which is a quantum of energy. Using E = hf, a photon's energy is directly related to its frequency (and hence its wavelength).

Only those wavelengths that correspond to a jump of an electron to a higher orbit are absorbed by the gas. Afterwards, the electron does not stay in its higher orbit and falls back down, emitting a photon of exactly the same frequency as the one absorbed. However, this is emitted in all directions, not just in the direction in which the electromagnetic radiation was originally travelling. If the material is a gas, this results in dark absorption lines seen in the spectrum when viewed through a spectroscope. The wavelengths of these lines shown are particular to particular elements, and allows for identification of elements present in stars and other gaseous objects that cannot be measured directly.

See also

External links


'"/>


(Date:4/17/2014)... A new modeling study suggests that fish consumption ... infant exposure to long-lived contaminants like persistent organic ... a team of researchers including University of Toronto ... Wania, looks at how different levels of environmental ... behavior of chemicals in the body influenced exposure ...
(Date:4/17/2014)... Kansas State University engineer has developed a patented ... improvised explosive devices. The same technique could help ... Steven M. and Kay L. Theede chair in ... engineering, and his research team have created a ... in car trunks. The distance detection method ...
(Date:4/17/2014)... Several parasites and pathogens that devastate honeybees in Europe, ... Africa, but do not appear to be impacting native ... team of researchers., The invasive pests include including ... East African honeybees appear to be resilient to these ... used to control pests in Europe, Asia and the ...
Breaking Biology News(10 mins):Fish consumption advisories fail to cover all types of contaminants 2Patented research remotely detects nitrogen-rich explosives 2East African honeybees are safe from invasive pests… for now 2East African honeybees are safe from invasive pests… for now 3
... PHILADELPHIAThe Academy of Natural Sciences today announced the revival ... an early 19th-century nature magazine of which only 13 complete ... Museum of Nature was published privately in London between 1810 ... one or two color plates. In it, Perry set out ...
... NY) Matthew Levy, Ph.D., assistant professor of biochemistry ... has been awarded more than $700,000 by Stand Up ... Levy,s work will focus on creating self-guiding drugs that ... serious or unpleasant side effects of current therapies. Dr. ...
... Just three months after the Euro 5 Norm ... car models, researchers at the Technische Universitaet Muenchen (TUM) ... meeting the more stringent Euro 6 emissions standard. A ... Chair of Internal Combustion Engines has succeeded in reducing ...
Cached Biology News:The Academy of Natural Sciences and Temple Press revive rare natural history work in new book 2Einstein receives high-risk/high-reward cancer research funding 2Einstein receives high-risk/high-reward cancer research funding 3Munich lab demonstrates diesel truck engine with barely measurable emissions 2Munich lab demonstrates diesel truck engine with barely measurable emissions 3
Other biology definitionOther Tags