The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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Our current understanding of atomic and molecular structure is based on the theory of quantum mechanics (also known as wave mechanics). The first major break with the classical mechanics of English physicist Isaac Newton (1642-1727) came with the proposal in 1900 by German physicist Max Planck (1858-1947) that energy is absorbed or given off by matter in small packets called quanta. Subsequent work by Albert Einstein (1879-1955) supported and extended Planck's quantum ideas. It was not until the revolutionary proposal by French physicist Louis de Broglie (1892- 1987) in 1923, however, that the pieces came together which resulted in the development of wave mechanics. De Broglie proposed that minute moving particles such as electrons, atoms, and molecules might possess certain properties commonly associated with waves, including a wavelength. The de Broglie relation that predicted the wave length (l) of a particle of mass (m) traveling at a velocity (v) is l = h/mv, where h is a universal constant known as Planck's constant (6.63 x 10- 27 erg-sec).
De Broglie's proposal was confirmed by Clinton Davisson (1881-1958), Lester H. Germer (1896-1971) and George P. Thomson (1892-1975) who observed that a stream of electrons is diffracted as it passes through a crystal which acts as a diffraction grating. This would be expected behavior for a wave but not for a particle unless it possesses wave properties.
In 1926 Austrian physicist Erwin Schrödinger (1887- 1961) combined the developing ideas of quantized systems and the wave nature of particles into a set of postulates which form the basis of wave mechanics, a theory that has led to a new understanding of the world of atoms and molecules.