machholtz light (FRET) ?

Hi,

The green glow visible in comet Machholtz is due to fluorescence resonance.
But the light absorbed by atoms then radiated by electrons displays the same
energy as the absorbed light, thus,

1°. if the light is green due to CN or C2 although the sun light is yellow,
does someone knows by hearth how many eV are requested for the electron to
emit this green light ?

2°. If the spin state of molecule changes, the radiation shifts to red
(H-alpha) or even IR. Do we know comets which coma displayed such peculiar
radiation in submm or mm wavelengths ? Or do we find it e.g., essentially in
bright nebula ?

Thanks in advance

Thierry
http://www.astrosurf.com/lombry