Radient energy vs nonradient energy

[jsomers]

Hi People

I am brand new to these forums and brand new to phyics (wells its been about 4 years so its safe to say I have pretty much forgotten everything but the basics)

Anyhow I am just beginning my PhD in Genetics where I will be using Förster resonance energy transfer to investigate the assembly of particular proteins. In my quest to understand the physics behind this phenomenon I came across this diagram:

http://www.olympusmicro.com/primer/techniques/fluorescence/fret/images/fretintrofigure3.jpg

What I don't really understand from it is what is the difference between radiant energy and non-radiant energy.

Forgive me if this is very basic but google has been little help so i thought id ask here.

Thanks for your time.

Jason

 

[sylas]

What I don't really understand from it is what is the difference between radiant energy and non-radiant energy.

Energy transferred by photons (electromagnetic radiation) is a radiant energy transfer.

Energy transferred by resonance, or by kinetic energy going from one atom to another, is non-radiant energy transfer.

Cheers -- sylas

 

[jsomers]

Wow that was simple, thanks for the speedy reply!

 

[Andy Resnick]

The transfer of energy does not invovle kinetic mechanisms, for FRET.

FRET is a non-radiant form of energy transfer by a dipole-dipole interaction. It's called non-radiant because there is no photon involved in the transfer of energy, only the evanescent (non-propagating) component of the electromagnetic field. This is why FRET experiments are sensitive to both separation distance and relative orientation of the two dipoles.

 

[sylas]

The transfer of energy does not invovle kinetic mechanisms, for FRET.

FRET is a non-radiant form of energy transfer by a dipole-dipole interaction. It's called non-radiant because there is no photon involved in the transfer of energy, only the evanescent (non-propagating) component of the electromagnetic field. This is why FRET experiments are sensitive to both separation distance and relative orientation of the two dipoles.

Ah. Thanks... and sorry if I lead jsomers up the garden path!

 

[jsomers]

Yeah, I have heard there is a fair bit of information you can draw from the occurrence of FRET that's why I am sure i'll be inhabiting these forums for the next three to four years to try to gain a greater understanding of my experiments!

 

[jsomers]

No stress sylas, you still provided me the answer to my question about radiant and non radiant. For a genetics crowd it is more then enough info.

 

[frankinstein]

On a some what similar note: The Einstein field equations couple c and the stress-energy tensor:

$$R_{\mu \nu} - {1 \over 2}g_{\mu \nu}\,R + g_{\mu \nu} \Lambda = {8 \pi G \over c^4} T_{\mu \nu}$$

Does this not imply that gravity is a radiating field of a photonic nature? Otherwise why would c be a component?

Frank