 Total angular momentum quantum number

The total angular momentum quantum number, often denoted by \( J \), is a quantum number that characterizes the total angular momentum of a quantum system. In quantum mechanics, angular momentum is a combined measure of both the orbital angular momentum and the intrinsic angular momentum (or spin) of particles. The total angular momentum \( J \) can be both a result of the orbital angular momentum \( L \) and the spin angular momentum \( S \) of the particles in the system.