Why can atoms only emit light at specific wavelengths

Posted on 03.06.2018 by Eula
When electrons go the other way down in energy level, light is emitted with that energy. Now another fact of quantum physics is that the wavelength of a photon a wave packet of light is inversely proportional to it's energy.

The electrons in an atom can only occupy certain allowed energy levels.

Only certain energy levels are allowed, so only certain transitions are possible and hence specific wavelengths are emitted when an electron drops to a lower energy level. Why do fluorescent bulbs only radiate certain wavelengths of light. It was discovered later that this didn't happen because electrons can only occupy discrete energy levels within the atom. Electrons move from a lower energy level ground state to a higher energy level only after the electron absorbs a specific quantum of energy. Because these electrons can only reside in levels of specific energy and thus only lose certain amounts of energy, they can only emit certain wavelengths of light. Conversely, an atomic electron can be promoted to a higher energy level when it absorbs a photon.
For example, you could have just as easily asked why an incandescent light bulb gives off white light rather than the spectral lines of tungsten, from which the filament is made. I could throw out a couple other less tested theories, but they, even if they sound good, most can only be tested by photoelectric detecting. These wave-functions behave according to rules that imply that electrons in atoms can exist only in certain energy states called levels. It's like the other answers, maybe with a bit of tweaks for why and how overall the processes causes the white light, though there is so much. Fluorescent lights work by ionizing atoms of mercury in the mercuryvapor in the tube, these ions then emit UV light. Classical physics predicted that a negatively charged electron would fall into a positively charged nucleus emitting a continuous spectrum of light as it did so. This was one of the early results of quantum mechanics.