1: The Path to Quantum Mechanics
- Page ID
- 455288
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- 1.1: Prelude to the Foundations of Quantum Mechanics
- Heisenberg and Schrödinger were inspired by four key experimental observations: the spectral distribution of black-body radiation, the characteristics of the photoelectric effect, the Compton effect, and the luminescence spectrum of the hydrogen atom. Explanation of these phenomena required the introduction of two revolutionary concepts: physical quantities previously thought to be continuously variable, such as energy and momentum, are quantized, and momentum and wavelength are related.
- 1.2: Blackbody Radiation Cannot Be Explained Classically
- All bodies emit thermal radiation spanning a broad range of wavelengths. • The amount and peak wavelength of the radiation depends on the temperature of the body, but not on its composition. • The higher the temperature, the more radiation is emitted and the shorter (or bluer) the wavelength of the bulk of the radiation.
- 1.3: Quantum Hypothesis Used for Blackbody Radiation Law
- Energy is quantized in some systems, meaning that the system can have only certain energies and not a continuum of energies, unlike classical mechanics.
- 1.4: Photoelectric Effect Explained with Quantum Hypothesis
- Einstein's theory of the photoelectric effect made the claim that electromagnetic radiation had to be thought of as a series of particles, called photons, which collide with the electrons on the surface and emit electrons when absorbed. This theory ran contrary to the belief that electromagnetic radiation was a wave and thus it was not recognized as correct until 1916 when Robert Millikan experimentally confirmed the theory
- 1.5: Matter Has Wavelike Properties
- Matter waves are often referred to as de Broglie waves and have wavelengths (λ) to its momentum, p, through the Planck constant, h: λ = h/p .
- 1.6: de Broglie Waves can be Experimentally Observed
- An electron, indeed any particle, is neither a particle nor a wave. Describing the electron as a particle is a mathematical model that works well in some circumstances while describing it as a wave is a different mathematical model that works well in other circumstances.