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Science

Sparse Crystals

John P. Schiffer

Published Jan 30, 1998• 4 citations
Publisher

Abstract

Atoms in ordinary matter are held together through bonds formed by electrons and are dominated by the rules of quantum mechanics. In a purely classical solid, however, an array of charged particles can be held together by electrostatic forces. In his research commentary, Schiffer discusses work reported in the same issue by Itano et al. in which the cubic ordering of a Coulombic crystalline solid has been observed for the first time.

DOI
10.1126/science.279.5351.675

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Atoms in ordinary matter are held together through bonds formed by electrons and are dominated by the rules of quantum mechanics. In a purely classical solid, however, an array of charged particles can be held together by electrostatic forces. In his research commentary, Schiffer discusses work reported in the same issue by Itano et al. in which the cubic ordering of a Coulombic crystalline solid has been observed for the first time.
Ordinary matter, composed of electrons and nuclei, is held together by Coulomb forces. These forces are potentially catastrophic for two reasons: the short range attraction could lead too a collapse while the long range repulsion and attraction could lead to an explosion or too strong interaction between macroscopic objects. The fact that neither of these things happens and that matter is essentially inert is a consequence of subtle properties of quantum mechanics and electrostatics outlined here.
In the scalar Aharonov-Bohm effect, a charged particle (electron) interacts with the scalar electrostatic potential U in the field-free (i.e., force-free) region inside an electrostatic cylinder (Faraday cage). Using a perfect single-crystal neutron interferometer we have performed a ``dual'' scalar Aharonov-Bohm experiment by subjecting polarized thermal neutrons to a pulsed magnetic field. The pulsed magnetic field was spatially uniform, precluding any force on the neutrons. Aligning the direction of the pulsed magnetic field to the neutron magnetic moment also rules out any classical torque acting to change the neutron polarization. The observed phase shift is purely quantum mechanical in origin. A detailed description of the experiment, performed at the University of Missouri Research Reactor, and its interpretation is given in this paper.
Even after extensive research in Quantum Mechanics, we are still unable to visualize instant-to-instant motion of an electron in hydrogen atom. That is because in QM treatment, potential energy term has been mistakenly assumed to be time-independent instead of depending on the instant-to-instant varying position of the orbiting electron [1]. This has led to wrong and weird solutions for the electron motion in hydrogen atom. Before the advent of wave mechanics, Sommerfeld model of elliptical electron orbits was able to explain most features of hydrogen spectra, except for the features associated with electron spin and magnetic moment interactions. However, the Sommerfeld elliptical orbits were of kinematic origin and could not provide visualization of instant-to-instant dynamic motion of the orbiting electron. Contrary to the QM perspective, we find that central core of the electron behaves as a classical particle while its electrostatic field behaves as a wave phenomenon. As such an electron under Coulomb force moves strictly in accordance with Newtonian laws of motion. In this paper, we develop dynamic electron orbits in hydrogen atom by using energy and angular momentum conservation principle in central force field. We have shown that during photon emission, angular momentum of the orbiting electron is changed by ħ due to recoil action. This may be the origin of various quantization rules. During emission of a photon, elliptical orbit transitions are also computed and plotted. Orbit transition time is of the order of 10-16 seconds. We have extended this methodology to compute electron orbits in hydrogen molecular bond and computed the H2 bond energy.