Atomic, molecular, and optical physics the origin of the index of refraction treated an electron in an atomic system classically according to the model of Paul Drude and Hendrik Lorentz. The theory was developed to attempt to provide an origin for the wavelength-dependent refractive index "n" of a material. In this model, incident electromagnetic waves forced an electron bound to an atom to oscillate. The amplitude of the oscillation would then have a relationship to the frequency of the incident electromagnetic wave and the resonant frequencies of the oscillator. The superposition of these emitted waves from many oscillators would then lead to a wave which
Cassandra (metaphor) representing the human moral conscience whose main task is to issue warnings. Cassandra as moral conscience, "predicts ill to come and warns that punishment will follow and grief arise". Cassandra's need to point out moral infringements and subsequent social consequences is driven by what Klein calls "the destructive influences of the cruel super-ego", which is represented in the Greek myth by the god Apollo, Cassandra's overlord and persecutor. Klein's use of the metaphor centers on the moral nature of certain predictions, which tends to evoke in others "a refusal to believe what at the same time they know to be