(AL)光譜問題送20點

1. 為什麼氫原子的發射光譜（emission spectrum）是線狀光譜（line spectrum）而不是連續光譜（continuous spectrum）？

The emission of hydrogen atoms comes from transistion of orbital electrons from a high energy level into a low energy level. Because energy levels (orbits) in an hydrogen atom are discrete, the energies emitted from these electronic transistions are also discrete, which resulted in the formation of a line spectrum. Each line in the spectrum corresponds to a transistion between two distinct energy levels.

2. 為什麼在一發射光譜中，譜線會隨著頻率增加（波長減少）而變得頻密及令其強度（粗幼）變弱？

Higher frequency emission indicates electron transistion from a very high energy level to a very low energy level (the ground state, for example). Since the separation between sucessive energy levels becomes smaller at very high levels, the difference in energy between transistions from very high levels to a low level is small. The lines in the spectrum would appear close to each other.

As the energy levels at very high orbits are close to each other, the chance for electronic transistion from these levels have been spreaded over a larger number of orbits, the number of emissions from any two transistion (which corresponds to a spectral line) thus becomes less and the spectral line decreases in intensity.