Corpuscular nature

A major conceptual problem associated with the idea of a photon is how to reconcile its corpuscular nature with a wave expanding in three dimensions. One way to address the problem starts from the wave function of a photon in an arbitrary state, expanded in terms of the general wave function (59) as... 

In the late nineteenth century, a whole set of experiments progressively lead to the conclusion that classical physics, namely, Newtonian mechanics, thermodynamics, and nascent electromagnetism, were unable to explain empirical evidence gathered by experimentalists. Scientists of that time were unable to conciliate two apparent contradictory aspects exhibited by radiation and matter. Some experiments demonstrated that light behaved like a wave, while others showed a rather corpuscular nature. On the other hand, electrons, protons, and the other massive particles would manifest wave-like properties in certain experimental conditions. 

The photoelectric effect is not only important as experimental evidence for the corpuscular nature of light but also finds applications in light detectors, and it is a fundamental process in photoelectrochemistry. 

To appreciate this time-lag, it is useful to recall that the electron was not recognized as an elementary particle until the twentieth century. Electron beams had been known as cathode rays since 1876, but their corpuscular nature was recognized only in 1897 [12]. The term electron was introduced in 1891 to designate the fundamental unit of electricity, namely the electric charge of a hydrogen ion [13]. Only later was it applied to Thompson s corpuscules, and it achieved general acceptance with Millikan s quite accurate determination of the electronic charge by the oil drop method [14,15]. 

Fundamental noise or random noise this type of noise is statistically distributed and its amplitude as a function of the frequency can be written as a sum of many sinusoidal functions. This type of noise is related to the corpuscular nature of matter or to the quantization of radiation, respectively, and cannot be completely eliminated. 

Einstein s postulate was later confirmed experimentally by A. Compton (1924). Noting that it had been fruitful to regard light as having a corpuscular nature,... 

We shall now cite a few more experiments, which seem to point unambiguously to the corpuscular nature of the a- and -rays. We attach special weight to the fact that it seems simply impossibb to understand these experiments from any other point of view than that we are actually dealing with discrete particles. In the next cha])ter, however, we shall discuss a series of experiments on these sjimc rays which seem to indicate just as indubitably that the rays represent a wave process. 

A second vivid proof of the corpuscular nature of these, rays is given by another method of counting the individual partichis. Tlic Qcuger counter (1913 G-eiger and Muller, 1928) consists essentially of a metal plate, placed opposite a metallic point (fig. 10) the whole is contained in an air-filled vessel. A potential difference is applied to the plate and point, as great as possible subject to the condition that in spite of the... 

Bohr had calculated the most accurately known experimental constant in physics by a method which was, to use a mild description, simply an outrage The corpuscular nature of light had come to stay it could no longer be ignored. No evangelist ever made so many converts in so short a time as did Bohr. 

One of the w atershed events in the development of physics and chemistry was the appearance of Einstein s landmark paper explaining the photoelectric effect, establishing the corpuscular nature of light, and leading to the modern view of the wave-particle duality of the microscopic realm. 

X-rays exibit corpuscular nature. Compton effect is the confirmation of this property. 

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