Subject |
is a kind of |
has definition |
fluorescence | emission | The emission of light at one wavelength, the green say, following absorption of light with a much shorter wavelength such as the ultraviolet. The UV photon parts with its energy by ejecting the electron into a high-energy level from which it cascades back down, releasing photons of lower energy and therefore longer wavelengths. A material which has this property is called a phosphor. |
Bowen fluorescence mechanism | fluorescence | A mechanism first discovered by Bowen which explains the anomalously strong lines of O III in the spectra of some planetary nebulae as fluorescence involving the radiative excitation of the 2p3d 3Po2 level of O2+ (54.71 eV) from the 2p2 3P2 state in the ground term by He II Lyman-α photons (54.17 eV). |