“The fine-structure constant derives its name from its origin. It first appeared in Sommerfeld's work to explain the fine details of the hydrogen spectrum. ... Since Sommerfeld expressed the energy states of the hydrogen atom in terms of the constant [alpha], it came to be called the fine-structure constant.” Quantum PhysicsHistory Of ScienceFine Structure ConstantFundamental Constants Book:Hydrogen: The Essential Element Source: Hydrogen: The Essential Element