Question

Why a linear spectrum is observed after hydrogen atom ionization?

Please I need really detailed description. May be some examples in nature, some schemes and some description based on basic relations. I want to understand it very well.

Answer 1

We often refer to spectrum as a continuous range of colors produced when light passes through a refracting medium such a crystal prism or a water droplet. The atomic spectrum, however is not continuous (this is why we call it a line spectrum) and may not be entirely in the visible range. It is produced by radiation emmited during electronic transitions inside the atom. We know from the quantum theory that electrons are allowed to have only certain energy states, but they can transition up or down by absorbing or emmiting energy, in the form of EM radiation of different frequencies. So each element can absorb and/or emmit a particular set of frequencies and this is actually one way to recognize its identity. Elements can be energized and its electrons exited by various methods, one of them is electric discharge on a gas contained in a vaccuum tube, exposed to a high potential difference. In this experiment we can see how the gas starts to glow. If this emmited light is passed through a prism or another optical device that does the job we can separete the constituent wavelengths, and this is called the emmision spectrum. The H has 4 visible lines, each of which correspond to a different electronic transition. The absorption line will be complementary to this one, we will see all the colors of the visible spectrum but this 4 wavelengths, where dark fringes will appear.