Bring fact-checked results to the top of your browser search. Applications of quantum mechanics As has been noted, quantum mechanics has been enormously successful in explaining microscopic phenomena in all branches of physics.
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|The Development of Quantum Mechanics | benjaminpohle.com||Click here to go to the Physics Virtual Bookshelf home page. Here we briefly outline some of the key features of these developments.|
Historical basis of quantum theory Basic considerations At a fundamental level, both radiation and matter have characteristics of particles and waves. The gradual recognition by scientists that radiation has particle-like properties and that matter has wavelike properties provided the impetus for the development of quantum mechanics.
Influenced by Newton, most physicists of the 18th century believed that light consisted of particles, which they called corpuscles. From aboutevidence began to accumulate for a wave theory of light.
At about this time Thomas Young showed that, if monochromatic light passes through a pair of slits, the two emerging beams interfere, so that a fringe pattern of alternately bright and dark bands appears on a screen. The bands are readily explained by a wave theory of light. According to the theory, a bright band is produced when the crests and troughs of the waves from the two slits arrive together at the screen; a dark band is produced when the crest of one wave arrives at the same time as the trough of the other, and the effects of the two light beams cancel.
Beginning ina series of experiments by Augustin-Jean Fresnel of France and others showed that, when a parallel beam of light passes through a single slit, the emerging beam is no longer parallel but starts to diverge; this phenomenon is known as diffraction.
Given the wavelength of the light and the geometry of the apparatus i. However, though the ideas of classical physics explain interference and diffraction phenomena relating to the propagation of light, they do not account for the absorption and emission of light. All bodies radiate electromagnetic energy as heat; in fact, a body emits radiation at all wavelengths.
The energy radiated at different wavelengths is a maximum at a wavelength that depends on the temperature of the body; the hotter the body, the shorter the wavelength for maximum radiation.
Attempts to calculate the energy distribution for the radiation from a blackbody using classical ideas were unsuccessful. A blackbody is a hypothetical ideal body or surface that absorbs and reemits all radiant energy falling on it. One formula, proposed by Wilhelm Wien of Germany, did not agree with observations at long wavelengths, and another, proposed by Lord Rayleigh John William Strutt of England, disagreed with those at short wavelengths.
In the German theoretical physicist Max Planck made a bold suggestion. He assumed that the radiation energy is emitted, not continuously, but rather in discrete packets called quanta. Planck showed that the calculated energy spectrum then agreed with observation over the entire wavelength range.
Furthermore, emission takes place as soon as the light shines on the surface; there is no detectable delay. Einstein showed that these results can be explained by two assumptions: The spectra of light emitted by gaseous atoms had been studied extensively since the midth century.
It was found that radiation from gaseous atoms at low pressure consists of a set of discrete wavelengths. This is quite unlike the radiation from a solid, which is distributed over a continuous range of wavelengths.
The set of discrete wavelengths from gaseous atoms is known as a line spectrumbecause the radiation light emitted consists of a series of sharp lines.
The wavelengths of the lines are characteristic of the element and may form extremely complex patterns.The subject of most of this book is the quantum mechanics of systems which have a small number of degrees of freedom. This book is a mix of descriptions of quantum mechanics itself, the general properties of systems described by quantum mechanics, and general techniques for .
I have been the proud owner and reader of "Quantum Mechanics Volume I" by Albert Messiah since the s. It is on the same set of shelves as "Quantum Mechanics Fourth Edition" by P.A.M.
Dirac, "Quantum Mechanics Third Edition" by L.I. Schiff, "Quantum Mechanics Second Edition" by E. Merzbacher, and "Quantum Mechanics" by A. Bohm. The history of quantum mechanics is a fundamental part of the history of modern benjaminpohle.comm mechanics' history, as it interlaces with the history of quantum chemistry, began essentially with a number of different scientific discoveries: the discovery of cathode rays by Michael Faraday; the –60 winter statement of the black-body radiation problem by Gustav Kirchhoff; the Applications of quantum mechanics.
As has been noted, quantum mechanics has been enormously successful in explaining microscopic phenomena in all branches of benjaminpohle.com three phenomena described in this section are examples that demonstrate the quintessence of the theory.
Quantum theory is the theoretical basis of modern physics that explains the nature and behavior of matter and energy on the atomic and subatomic level.
The nature and behavior of matter and energy at that level is sometimes referred to as quantum physics and quantum mechanics. Planck wrote a. Quantum mechanics is the science of the very small. It explains the behavior of matter and its interactions with energy on the scale of atoms and subatomic benjaminpohle.com contrast, classical physics only explains matter and energy on a scale familiar to human experience, including the behavior of astronomical bodies such as the Moon.
Classical physics is still used in much of modern science and.