Quote:
Originally Posted by CraigS
Ok. So now I've found another relevant, (to spectra discussions), paper published 14th Jun 2010:
Detection of parent H2O and CO2 molecules in the 2.5–5 μm spectrum of comet C/2007 N3 (Lulin) observed with AKARI (700kB).
The spectrum is on page 14 and it is interesting to compare it with Hartley's (over, roughly the same, 2.5 to 5 micron band). Nowhere near as much CO2 as Hartley 2 .. a little more H2O though, and similar hydrocarbons (incl CO v(1–0) at 4.67 μm, organics at 3.2–3.6 μm) .. similar, but different to Hartley 2. They talk about a combination of CO, CO2, and dust thermal emissions at 4.5 μm, H2O 'emission' region of 2.7–2.8 μm.
I'm unclear as to whether they actually mean emission or absorption lines. (???).
The paper is an interesting read as it talks about up-to-date near-infrared and infrared detection limitations as well as about the spectra lines and their causes.
Cheers |
Craig,
IR is low energy. What you see are absorption lines. There is not enough energy to excite electrons into higher energy levels resulting in emission lines when the electrons return to the ground state.
As you decrease the wavelength of the radiation, the energy increases.
Visible and UV radiation will push electrons into higher energy levels. X-rays can remove electrons completely from a chemical bond resulting in ionization, gamma rays are the mother of all photons, apart from completely stripping an atom of it's electrons they can destroy the nucleus.
Regards
Steven