What is meant by quantum leap in atomic physics?

A quantum leap in atomic physics refers to an electron's sudden jump from one energy level to another within an atom.

In more detail, the term 'quantum leap' or 'quantum jump' is a fundamental concept in quantum mechanics, the branch of physics that deals with phenomena on a very small scale, such as molecules, atoms, and subatomic particles. This concept is based on the principle that energy is quantised, meaning it comes in discrete amounts rather than a continuous range.

In the context of an atom, the energy levels are the specific states that an electron can occupy. Each energy level corresponds to a certain amount of energy that the electron has. When an electron absorbs or emits energy, it can 'jump' from one energy level to another. This is what is referred to as a quantum leap.

It's important to note that these leaps are not gradual transitions but instantaneous changes from one state to another. The electron does not exist in the space between energy levels during the leap. This is a significant departure from classical physics, which would predict a smooth transition between states.

The energy absorbed or emitted during a quantum leap is often in the form of a photon, a particle of light. The energy of the photon corresponds to the difference in energy between the initial and final energy levels of the electron. This is the basis for the creation of light and other electromagnetic radiation.

For example, when an electron in a hydrogen atom makes a quantum leap from a higher energy level to a lower one, it emits a photon with a specific energy. This energy corresponds to a specific wavelength of light, which is why hydrogen gas glows with a characteristic colour when it is excited.

In summary, a quantum leap is a sudden, discrete change in an electron's energy level within an atom, a fundamental concept in quantum mechanics.