Bohr Radius

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Bohr radius

[′bȯr ‚rād·ē·əs]
(atomic physics)
The radius of the ground-state orbit of the hydrogen atom in the Bohr theory.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Bohr Radius


the radius of the first (closest to the nucleus) orbit of an electron in a hydrogen atom, according to the atomic theory of N. Bohr; it is represented by the symbol a0 or a. The Bohr radius equals (5.29117715 ± 0.0000081) x 10-9 cm ≈ 0.529 angstroms; it is expressed by the universal constants: a0 = h2/me2, where h is Planck’s constant divided by and m and e are the mass and electric charge of the electron. In quantum mechanics, the Bohr radius is defined as the distance from the nucleus at which the electron is observed with the greatest probability in an unexcited hydrogen atom. [3–1673–4; updated]

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
From the equations above, we see that lowest Bohr radius varies as 1/[m.sup.2], and the orbital frequency as [m.sup.3].
In this regard, theory suggests that, for this to be the case, the radius of the QD should be less than the bulk exciton Bohr radius, calculated as [a.sub.B] = [epsilon][[??].sup.2]/[mu][e.sup.2], with [epsilon] and [mu] being, respectively, the dielectric constant and the reduced mass of the electron and hole.
where [a.sub.0] is the Bohr radius and v the electron pulsation (E = h v).
Section 4 will recall some useful inequalities that we shall need and Section 5 focuses on recent applications of Holder's inequality for mixed sums in Functional Analysis and Quantum Information Theory, culminating with the solution of a classical problem from Complex Analysis: the Bohr radius problem.
When the size of semiconductor nanocrystals is smaller than the Bohr radius of the excited electron-hole pair, quantum confinement effect occurs and the band gap energy starts to increase with the decrease of particle size.
The results obtained in this paper were calculated taking into account the values of the effective "Bohr radius" [a.sup.*.sub.0] = 9,87nm and the Effective Rydberg constant [R.sup.*.sub.y] = 5,72 meV.
With the introduction of Rydberg scale, the effective Rydberg energy is defined as [R.sup.*] = [m.sup.*.sub.e][e.sup.4]/2[[??].sup.2][[epsilon].sup.2.sub.0] and the effective Bohr radius as [R.sup.*.sub.B] = [[??].sup.2][[epsilon].sub.0]/[m.sup.*.sub.e][e.sup.2], and hence, the values of these quantities, for GaAs semiconductor, become [R.sup.*] =5.28 meV [R.sup.*.sub.B] = 103 [Angstrom].
Bulk CdSe is a direct bandgap (1.74 eV) II-VI semiconductor with an exciton Bohr radius of 6 nm [11,12].
Since the uniform circular motion of an electron is in opposition to Heisenberg's Uncertainty Principle (actually [DELTA]r = 0 and [DELTA]mv = 0), my correction to special relativity allows me to consider that when the electron tends to stop, it oscillates around the origin of the x-axis with an amplitude equal to the Bohr radius and it moves (on average) with twice the minimum speed.
Using the above given parameters of GaAs (x = 0) one can obtain the effective Bohr radius and the effective Rydberg energy as [??] 101 [Angstrom] and [??] 5.72 meV, respectively.
The constant [a.sub.0], the Bohr radius, gives the scale of the interaction and [gamma] is the relativistic correction factor.