Sentences with phrase «absorb photons at»

The young chemist did not know why the resulting color was so vivid; the ability of molecules to absorb photons at specific wavelengths based on the structure of their shared electron bonds would not be worked out for another fifty years.

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

Molecules absorbing photons at a depth of 1 mm will likely loose that energy to the bulk by molecular collision.

A molecule that absorbs a photon at a specific wavelength absorbs a specific quanta of energy and releases the same amount on emission — the quantum effect.

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.

It absorbs and reemits some light from the surface, but it also emits its own UV light, making it difficult to identify where the photons originated, says Bart de Pontieu, the science lead for IRIS at the Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto, Calif..

But just as something painted black is very good at both emitting and absorbing heat, a semiconductor that is very good at emitting photons is also very good at absorbing them.

If an atom absorbs a single photon, its change in velocity is tiny compared with the average velocity of atoms in a gas at room temperature.

A study in the journal Nature Materials details the creation of a nanowire - based technology that absorbs solar energy at comparable levels to currently available systems while using only 1 percent of the silicon material needed to capture photons.

That's because the gas can be used to make several of the layers in a silicon photovoltaic — from the top of the cell where it is used to deposit a layer of silicon nitride that ensures that all sunlight is absorbed, to the bottom where it can be used to deposit another layer that helps reflect back any missed photons of sunlight, boosting the efficiency of the cell at converting light into electricity.

Photons with too little energy «will just sail right on through» the light - catching layer and never get absorbed, says Daniel Friedman, a photovoltaic researcher at the National Renewable Energy Lab.

If atoms are exposed to several laser beams with carefully chosen polarization and frequency values, then they preferentially absorb photons from the forward hemisphere, where the photon angular momentum and the atomic velocity are at an angle larger than 90 degrees.

OCO - 2 will also closely monitor the carbon uptake of plants by measuring the weak fluorescence that is produced during photosynthesis as plants» chlorophyll pigments absorb light to capture energy and subsequently re-emit photons at longer wavelengths.

Peering through a viewport, I watch as a blob of atoms absorbs photons of laser light and re-emits them at slightly higher energies, losing a bit of heat each time.

(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.

As the frequency of the electric field of the infrared radiation approaches the frequency of the oscillating bond dipole and the two oscillate at the same frequency and phase, the chemical bond can absorb the infrared photon and increase its vibrational quantum number by +1.

If there is a greater density of CO2 molecules, then the probability of a particular photon, at one of these wavelengths that CO2 absorbs, coming across a CO2 molecule, is clearly increased.

What credible observers simply propose is the slight modulation of solar irradiance at the source, solar L1, using opaque thin films, preferably thin films that absorb and convert solar photons into storable energy of some sort, or simply sold off or beamed away.

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).

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

Ray: «The IR flux from the warmer surface excites much of the CO2 — much more than would be excited at thermal equilibrium at the temperature of the atmospheric layer where the photon is absorbed.»

, then the interaction gets complicated, but if we stick to purely complete emission and absorption of photons, with any scattering preserving photon energy, then, if the non-photons within each local system are at LTE, then they will emit into a direction as much as they absorb from a direction of the same type of photons if their temperature is the same as the brightness temperature of the incident photons.

How long does a CO2 molecule at 5.5 kms height hold on to that absorbed IR photon before it is released (emitted or transferred though collision to another atmospheric molecule)?

This also means there are more absorbed photons in the atmosphere at any one time (the atmosphere is hotter).

Radon is radioactive, and if it were present at 400 ppm, collisions of neutrons with neighboring air molecules would cause more warming than an equivalent concentration of CO2 by absorbing relatively weak infrared waves / photons.

To address these challenges, the Molecular and Nanoscale Interfaces Project aims to couple light absorbers, catalysts, and half - reactions for optimal control of the rate, yield, and energetics of electron and proton flow at the nanoscale, so that complete macroscale artificial photosynthetic systems can achieve maximum conversion of solar photon energy into the chemical energy of a fuel.

BTW, in case you didn't get it, the basic error by Tom is demanding that there be LTE at all times, even when a photon of IR from outside the local area is absorbed.

At certain wavelengths a radiatively active gas will absorb photons and then reemit them in a random directions.

For this study, we fixed the photosynthetic capacity at 0.05 mol C per mol photon (2.75 gC · MJ − 1 of absorbed photosynthetically - active radiation).

Help me here... A system in equilibrium quickly returns to equilibrium at a higher level when it absorbs an IR photon: CO2 + N2CO2 + N2 becomes CO2 * + N2CO2 + N2 + (pardon the limited special character skills).

My understanding is that approximately 85 % of all photons in the Earth's blackbody spectrum that are also in the absorbtion spectrum of CO2 are already presently being absorbed at the present concentration of atmospheric CO2.

How does a CO2 molecule, somewhere up in the middle troposphere, KNOW that it is only allowed to absorb upwelling radiation photons from the surface and must ignore all the other photons coming at it from all around in the atmosphere?

Due to the long photon emission time (every photon is absorbed and re-emitted many times) the star photosphere is at a pseudo equilibrium allowing a black body approximation for mean photosphere temperature.

The standard tables for absorption of photons by CO2 show that at STP, 50 % of photons are absorbed within 25m and 50m for wavenumbers 650, and 700 respectively.

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.

Since those 15 micron photons are impacting a surface that is already radiating away from the hugely more massive surface (speaking at molecular level) those photons will be absorbed and radiated out again because the heat store just below the molecular surface is at a higher energy potential.

Radiation at these wavelengths can not be radiated directly into space from the surface because these photons are easily absorbed by water and CO2 molecules.

Strictly speaking there is a small probability that a molecule at the surface that has just absorbed a photon will emit again before it can transfer the energy by collision with other molecules, but that probability is very small, < 1E - 04.

First, we must remember that the surface of the ocean emits some photons at wavelengths (the «window») where GHG's can't absorb them.

I would not be surprised if my numbers are off by 10x or possibly even 100x, but that still doesn't cahnge the fact that there are plenty of CO2 molecules around to absorb photons even at an «insignificant 0.04 %» concentration.)

The fine structure is still clearly visible at 80m, and less than 95 % of the photons between 650 and 690 cm - 1 are absorbed in 80m.

But having arrived at that point and having been absorbed, the photon gets re-emitted in a random direction.

Or put another way, if there is so much water vapor around (3 % vs only 390ppm for CO2), and more GHGs means more warming, why does the GHE stop at 33C instead of continuing until all the water vapor absorbs a photon OR asked another way, who says that all the water vapor caused by the added CO2 will absorb a photon to cause more GHE warming?

This dye absorbs the photon, and re-emits a photon at a lower wavelength.

If a cold greenhouse gas absorbs a photon emitted from the ground, and emits at a lower intensity, where does the rest of the energy go?

Organic compounds can not absorb in the infrared but are good at combining two lower energy photons to a higher energy photon.

Ira Glickstein, PhD says: February 28, 2011 at 11:08 pm What the 100 % absorption means is that 100 % of the photons in the appropiate bands are 100 % likely to be absorbed by an H2O or CO2 molecule before they travel all the way through the Atmosphere.

Then consider all of THOSE factors in terms of what wavelength of photons are being release and what wave length are being absorbed at any given point in time based on all of those factors and map that against the atmospheric window....

Indeed, I believe, even at the historical 270 or 280 ppm level of CO2, each photon traveled a small fraction of the height of the Atmosphere before being absorbed and re-emitted.

Yes, you used the reflections to account for decreasing energy states by increasing the wavelengths, to points where the photons would finally be absorbed by the N2 at its «supposed» absorption spectra.