## gerryliyana Group Title [1/2] i'll bring topic about Molecular spectroscopy. Listen to me. "In the UV, visible and IR regions it is an experimental fact that a given sample continues to show an absorption spectrum for as long as we care to irradiate it -- in other words, a finite number of sample molecules appears to be capable of absorbing an infinite amount of energy. Plainly the molecules must be able to rid themselves of absorbed energy. one year ago one year ago

1. gerryliyana

[2/2] A possible mechanism for this is by thermal collisions. An energized molecule collides with its neighbours and gradually loses its excess energy to them as kinetic energy – the sample as a whole becomes warm. Another mechanism is that energy gained from radiation is lost as radiations once more. A molecule in the ground state absorbs energy at the frequency $$\nu$$ and its energy is raised an amount $$\Delta E = h \nu$$ above the ground state. It is thus an excited, unstable condition, but by emitting radiation of frequency $$\nu$$ again, it can revert to the ground state and is able to re-absorb from the radiation beam once more In this case, it is often asked "HOW AN ABSORPTION SPECTRUM CAN ARISE AT ALL, SINCE THE ABSORBED ENERGY IS RE-EMITTED BY THE SAMPLE?""

2. gerryliyana

a discussion has been opened :)

3. gerryliyana

@abb0t , @brittneyy18rm , @ivanmlerner , @geerky42

4. gerryliyana

@Gabylovesyou

5. gerryliyana

@ScienceGuy

6. ScienceGuy

I'm sorry but I'm tied up with a few students right now. If I finish them off I'll be more than happy to consider your question.

7. Phloyd

good question ...leads me to one of my own arguments of energy having mass ( no worries i wont go there ) in 2/2 you mentioned energy loss due to collision / kenitic enegy ... can we look at this not as energy loss but as energy tranferance ( simular to biological cell division but in this case case what is being noted as energy loss in the collision could be " birth of sub atomic particles of energy " in your 2nd mec in 2/2 i am reminded of a hot air balloon in this case the molecule will is represent the hot air balloon , on the ground having its own energy ... the bam the the energy gets excited raises ...( now this is where i think energy has mass / atomic wt ) for the molecule to decend again after the 2nd blast of rad ... or the molecule is weakened unable to sustain the 2nd blast .....well thats my 2 bits hope it helped

8. Mashy

I think both hold good.. a) collision theory .. cause basically heat is nothing but kinetic energy of the molecules.. but not just that.. it also makes its surrounding hot.. so definitely energy is lost by giving it away to the surrounding (heat transfer).. b).. definitely the atoms get excited and deexcited again.. cause if they didn't get de excited.. then wouldn't get excited again.. and then we wouldn't have absorption spectra in the first place.. so why do we get absorption spectra if they do deexcite.. well.. when they de excite.. the photon of energy they release can go in any random direction.. and the energy released is SOOO small.. that even if some photons do make it in the direction of the screen, they would be absorbed somewhere or the other.. and its also possible that the released photon excites some other atoms of the same sample!.. just my views :P

9. gerryliyana

i thank all of u for attention.., nice @Phloyd for ur great argument, but what do u mean by "birth of sub atomic particles of energy" ?

10. gerryliyana

Wow, its remarkable idea @Mashy , so, the radiations is re-emitted in a random direction and and re-emitted radiation has as much chance of reaching the source as the detector, the net effect, then, is an scattering into surroundings.