The color of light that is emitted by an atom depends on how much energy the electron releases as it moves down different energy levels. When the electrons return to lower energy levels, they release extra energy and that can be in the form of light causing the emission of light. On the other hand, absorbed light is light that isn't seen. Absorption occurs when electrons absorb photons which causes them to gain energy and jump to higher energy levels. Notice emission in the picture above.
It shows the electron moving down energy levels. The color of the light emitted would result from the amount of energy as it moves through shells. Absorption is shown by the energy levels increasing as the photon gains energy. The wavelengths shown relate to the amount of energy in the photon. Notice how the emitted light wavelengths are shorter than the absorbed light wavelengths.
This would indicate that the emitted light has more energy in the photon than the absorbed light. This is important because it shows the shells that electrons move to when light is absorbed or emitted. The energy difference between orbitals can be calculated by measuring the frequency of radiation. Absorption and emission of light can reveal a lot about the structure of an atom. Absorbed light is light that isn't seen while emitted light is light that is seen.
Emission is when electrons return to energy levels. While the sun gave the colors of the rainbow, the flames had light in very distinct lines or bands. This puzzle was finally resolved a little more than years ago with the invention of quantum mechanics, which basically says that the electrons zooming around atoms and molecules and the vibrations and rotations of molecules can have only discrete energies that are governed by rules of conservation of angular momentum.
The following bulleted list is a crash course in absorption by the electrons in atoms and molecules. Refer to the figure below the box. Otherwise, the atom or molecule will not absorb the light. Once the molecule has absorbed the photon, it can either lose a photon and go back to its original lower energy level; or it can break apart if the photon energy is greater than the chemical bond holding the molecule together; or it can collide with other molecules, such as N 2 or O 2 , and transfer energy to them while it goes back to its lower energy level.
Collisions happen often, so the energy of the absorbed photon is often transferred to thermal energy. Note that Earth's outgoing infrared irradiance is limited to a few atmospheric "windows" and the irradiance at all other wavelengths is strongly absorbed, mostly by water vapor, but also by carbon dioxide, ozone, nitrous oxide, methane, and other more trace gases that aren't shown in the figure above.
Skip to main content. Print 6. The blue color results from selective absorption of radiation with wavelengths at the red end of the visible spectrum. In the figure below that shows the wavelength dependence of absorption by different molecules, you can see that water vapor has absorption in the red part of the visible spectrum, starting at about nm 0.
Credit: Dominic Alves via flickr. Crash Course: Absorption by the Electrons in Atoms and Molecules Chemical bonds and quantum mechanics together determine the energy levels that any electron, atom, or molecule can be in. The energy of a molecule is the sum of the energy related to the position of electrons relative to their stable ground electronic states, the molecular vibration, and the molecular rotation.
Rules set by conservation of angular momentum and electron spin determine which transitions between energy levels are allowed. It decays to orbit at a fair fraction of lightspeed just inside the nuclear surface.
Selection rules for hadrons and leptons are different. They may not see each other. Reaction path is defined by conservation of orbital symmetry. Tetra- tert -butyl tetrahedrane does not thermally fragment. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. A molecule absorbs light having a specific wavelength, why doesn't it absorb shorter wavelengths?
Ask Question. Asked 7 years, 7 months ago. Active 3 years, 4 months ago. Viewed 4k times. Improve this question. Gaurang Tandon 8, 10 10 gold badges 55 55 silver badges bronze badges. I think the answer is that it can happen. I overheard something about electronic Raman scattering the other day, which would be something like what you described, but trying to read the material on it just hurts my head too much for me to delve into it right now. Show 1 more comment. Active Oldest Votes. Quantum approach Compound energy levels are quantized , so compounds can absorb only some discrete energy values.
Improve this answer. Community Bot 1. G M G M 8, 33 33 silver badges 60 60 bronze badges.
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