The Classical origin of the oscillator strength
Abstract The concept of oscillator strength is useful in various areas of chemistry and physics, such as radiation emission and absorption, dielectric constant, refractive index, and inelastic collisions between charged particles and atoms and molecules. In most textbooks, the concept of oscillator force is introduced ad hoc, with little or no mention to its classical origin. In this article, the classical origin of the various parameters that describe the intensity of the optical transitions in atoms and molecules are reviewed, with emphasis on the concept of oscillator strenght, that makes t e connection between those parameters. Some misconceptions and common pitfalls regarding these quantities are pointed out.