>>13098360But first! Things that are warm radiate light depending on just how hot they are. For things like the sun, that are a few thousand Kelvins, this is high enough energy to be in the visible region. For things like people, or just normal earth temperatures, this is in the IR spectrum. Because this can still warm things up, you get things like the greenhouse effect, which is just reabsorbing the energy given off by other things cooling down. For CO2, a certain bending motion is right at an energy that other parts of the atmosphere miss, so as you have more CO2, more CO2 can be excited on this vibration, and then have that transfer over to kinetic energy.
For UV/vis, you'll have an electric transition. In this, you have the electrons themselves jump to a higher energy state. It's basically like you have a helium electron that gets a big wad of energy and starts acting the fool like it's a lithium electron. It's a more complicated or farther away motion, and it has more energy. But now it's not doing its job of bonding quite so good. It's out partying, and then, oops, it made another bond. Or maybe it was locking one bond in place, stopped, that bond rotated and when it came back (they always come back), the bond wasn't what it used to be. This is what happens with 11-cis-retinal, or the molecule your eyes use to see. When that goes to all-trans-retinal, it unlocks a chemical cascade that pumps a the cell full of ions, which is an electrical current that goes to your brain, which no one understands. Most electronic transitions are actually higher than that transition, so it that light isn't absorbed by your eyes, and it's invisible to you.
For gamma radiation, the electron gets energy that's so high it kindly removes itself from the molecule all together. (They don't always come back).
