Free Electrons in Quantum Mechanics

2009 ◽  
pp. 93-118
Keyword(s):  
Quantum Mechanics ◽  
Free Electrons

scholarly journals Doubly and Triply Differential Cross Sections for Single Ionization of He by Fast Au53+ Using a Multi-Body Quasiclassical Model

Atoms ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 19
Author(s):  
François Frémont
Keyword(s):  
Quantum Mechanics ◽  
Cross Sections ◽  
Differential Cross ◽  
Present Model ◽  
Differential Cross Sections ◽  
Free Electrons ◽  
Single Ionization ◽  
Multi Body ◽  
Better Than ◽  
Binary Peak

A multi-body multi-center quasiclassical model was used to determine doubly- and triply-differential cross sections following single ionization in 3.6 MeV/amu Au53+ + He collisions. The present model improved recent calculations, in which free electrons were added in the collision to reproduce, at least qualitatively, the experimental binary peak. In the present calculations, the electrons, that were assumed to originate from the collisions of Au53+ with surfaces before colliding with the He target, were now considered to be in the field of the projectile, with nearly the same velocity. The agreement between the calculations and the experiment was improved, for both the doubly- and the triply-differential cross sections and was better than previous calculations based on quantum mechanics.

scholarly journals The quantum mechanics of electrolysis

1931 ◽  
Vol 134 (823) ◽  
pp. 137-154 ◽  
Keyword(s):  
Quantum Mechanics ◽  
Irreversible Processes ◽  
Physical Processes ◽  
Free Electrons ◽  
Spontaneous Transition ◽  
Valence Electrons ◽  
A Cell ◽  
Great Contrast ◽  
Gas Electrodes ◽  
A Current

As quantum mechanics endows particles with entirely new properties, it enables us to deal with problems which have remained unsolved for many years. In electrolysis we have been unable to visualise the physical processes which underlie some of the most elementary phenomena. Thermodynamics gives a consistent account of them, independent of any mechanism; but when we try to unravel the actual processes their complexity is baffling. Quantum mechanics provides a new line of attack. One conception we find for our purpose particularly valuable—the idea that there always exists a finite probability of a particle making a spontaneous transition between any two states of equal energy. In the Sommerfeld theory of metals the valence electrons of the metallic atoms are all free electrons, so that we may regard the atoms of the metallic crystal as ions. Applying this to the anode of a copper voltameter, for example, we may say that when a current is passed, ions from the crystal lattice are leaving the surface of the electrode and slipping away into solution. The same is true of reversible gas electrodes. In great contrast to this are the processes at the electrodes of a cell where an acid is being decomposed by electrolysis. Here ions from the electrolyte are being neutralised by actual capture and loss of electrons, evolving neutral oxygen and hydrogen. Thus the phenomena of electrolysis fall into two classes, both of which may be treated by quantum mechanics. In the electrolysis of acids we encounter the complicated phenomena of “overpotential,” which provides an elaborate test for our theory; for this reason we shall be dealing in this paper with only these irreversible processes.

Dynamic studies of silicide-mediated crystallization of amorphous silicon

1992 ◽  
Vol 50 (2) ◽  
pp. 1352-1353
Author(s):  
C. Hayzelden ◽  
J. L. Batstone
Keyword(s):  
Ion Implantation ◽  
Solid Phase ◽  
Metallic Phase ◽  
Single Crystal Substrate ◽  
Free Electrons ◽  
Melt Temperature ◽  
Transmission Electron ◽  
Crystal Substrate ◽  
High Resolution Tem

Epitaxial reordering of amorphous Si(a-Si) on an underlying single-crystal substrate occurs well below the melt temperature by the process of solid phase epitaxial growth (SPEG). Growth of crystalline Si(c-Si) is known to be enhanced by the presence of small amounts of a metallic phase, presumably due to an interaction of the free electrons of the metal with the covalent Si bonds near the growing interface. Ion implantation of Ni was shown to lower the crystallization temperature of an a-Si thin film by approximately 200°C. Using in situ transmission electron microscopy (TEM), precipitates of NiSi2 formed within the a-Si film during annealing, were observed to migrate, leaving a trail of epitaxial c-Si. High resolution TEM revealed an epitaxial NiSi2/Si(l11) interface which was Type A. We discuss here the enhanced nucleation of c-Si and subsequent silicide-mediated SPEG of Ni-implanted a-Si.Thin films of a-Si, 950 Å thick, were deposited onto Si(100) wafers capped with 1000Å of a-SiO2. Ion implantation produced sharply peaked Ni concentrations of 4×l020 and 2×l021 ions cm−3, in the center of the films.

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