Sentences with phrase «which absorbs photons»

Photovoltaic cells, which absorb photons from sunlight and convert them to electricity, operate with only 20 percent efficiency.

Two key properties of fluorophores that determine brightness are the extent to which the excitation light is absorbed and the efficiency by which absorbed photons are converted into emitted photons.

Not exact matches

Photons that enter the crystal at one end bounce back and forth between these «mirrors» a few thousand times before they can escape, which increases their likelihood of getting absorbed by an atom along the way.

Crystal quantum memory devices hoard data by absorbing photons, each of which carry one quantum bit, or qubit, of data.

This sends the crystal into a quantum superposition, in which many thulium ions absorb the photon at once and vibrate at different frequencies.

By careful construction of the avalanche region, it is possible to build an APD which generates an output, or gain, of 1500 electrons for every photon which is absorbed.

TiO2 absorbs photons, which excite electrical charges in the catalyst.

Sunlight would strike the top electrode, which would absorb photons and catalyse the water - oxidation process.

Upon exposing a metallic surface to electromagnetic radiation that is above the threshold frequency or threshold wavelength (which is specific to the type of surface and material), the photons are absorbed and current is produced.

But photons can only travel so far through air or optical fibers before the material absorbs the particles, limiting the distance over which communication is possible.

The first stage absorbs light in the form of photons and uses it to produce energy storage molecules, which are then used to power the second stage, which fixes carbon from the air into carbon - based sugars, such as sucrose and starch.

When light hits a painting, some photons are absorbed by pigment molecules, which split apart.

The universe is opaque to ultraenergetic photons, or gamma rays, which are absorbed by the matter and radiation that lie between their source and Earth.

(Cognoscenti will have noticed that I have skipped past a third process, stimulated emission, in which a photon arriving at a molecule that is already excited causes it to emit, instead of absorbing that photon.

Vibrational modes in molecules with three or more atoms (H2O, CO2, O3, N2O, CH4, CFCs, HFCs...) include bending motions that are easier to excite and so will absorb and emit lower energy photons which co-incide with the infrared radiation that the Earth emits.

The higher energy ultraviolet photons, which can be absorbed by O2 molecules in the stratosphere, break that oxygen - oxygen bond and the freed oxygen can combine with O2 to make ozone (O3).

I don't have a mathematical argument for my claim, just a physical one, which is that as photons pass through a gas they're either absorbed or not.

The frequency at which photons are emitted or absorbed is small relative to the rate of energy redistribution among molecules and their modes, so the fraction of some molecules that are excited in some way is only slightly more or less than the characteristic fraction for that temperature (depending on whether photons absorption to generate that particular state is greater than photon emission from that state or vice versa, which depends on the brightness temperature of the incident radiation relative to the local temperature).

The details on a molecular level determine how likely a given transition is likely to occur — in other words, the fraction of photons of some frequency, polarization, and direction, that are absorbed over some path through an amount of material, and the number of photons of the same type which are emitted per unit time.

When you say the optical depth is the depth at which (on average) a photon is absorbed, shouldn't that be absorbed or scattered.

Does this mean it can absorb up to 4 IR frequency photons (hence causing vibration), after which it effectively becomes IR transparent?

So the surface of the Earth absorbs two identical 15 micron photons which carry the same energy, one originates from a colder CO2 molecule and the other from the surface of the Sun.

If the CO2 simply re-emits the LW photons it absorbs, then how does it heat the air, that is the N and O2, which is what the greenhouse effect does?

The GHGs like CO2 do emit photons, which go up and down, but they are not the photons that they absorb.

You do know that plant life absorbs photons and CO2, which is buffered by inorganic carbonate, and convert it to organic carbon.

So when a molecule absorbs a photon (which, by definition results in an excited vibrational and / or rotational state) the very process of re-establishing equilibrium means that some of that energy winds up in translation.

That implies that an excited electron in a greenhouse gas molecule in the atmosphere can not radiate toward the ground unless it can «find» another electron on the surface in a ground state which is capable of absorbing the photon which is to be radiated.

The proposition is that every photon that is emitted is certain to be absorbed at some location in the universe and that an electron can not emit except when in resonance with another which can absorb.

Most photons are absorbed lower down and cause molecules to evaporate indirectly by providing energy to the skin layer, which is then available to the evaporating molecules via convection and conduction.

Plants absorbs high energy photons, which results in the combining of CO2 and H20 into CH2O and O2.

So in the Earth surface up there will be a reasonable flux of 15um photons which can be absorbed to increase the active population.

Phil, what do your calculations give for the distance in which the first - generation photons from the Surface up into the atmosphere are absorbed to extinction in CO2's case?

In which case the water vapor associated GHE is due to directly absorbed photons?

So Gavin, you are claiming that in the GHE when a photon comes in it sits around in the air until man releases CO2 which results in warming which results in more water vapor which THEN absorbs the energy photon to create feedback?

As I understand AGW, the theory goes that added CO2 combines with an energy photon (ie the greenhouse effect) to warm the world, & heat the air which results in more water vapor which absorbs more photons which results in Man caused warming feedback.

Calculations need to be done which shows how many more photons are absorbed which cause how much more collision interactions, since this is where the heat comes from in the atmosphere.

ANY electro - magnetic radiation (waves or photons), of ANY wavelength is capable of giving rise to waste «heat» when absorbed in the proper medium; but THERMAL RADIATION is a special kind of EM radiation which is produced entirely because of the mechanical oscillatory modes of ordinary materials, and is dependent on the Temperature for its characteristic Spectral envelope.

The discrete energy levels can only absorb the exact wavelength corresponding to their energy separation, they don't absorb a photon which has too much energy and then discard the excess!