| 释义 |
magneton Physics.|ˈmægnɪtɒn|
[ad. F. magnéton (P. Weiss 1911, in Compt. Rend. CLII. 189), f. magnéti-que magnetic a.: see -on1.]
Any of several units of magnetic moment used in atomic and nuclear physics: Bohr magneton [Bohr], a unit that arises naturally in Bohr's theory of the atom, equal to eh/4πm (where e and m are the charge and mass of the electron, and h is Planck's constant, in S.I. units), i.e. about 9·27 × 10-24 joule per tesla; nuclear magneton, a unit used for expressing nuclear magnetic moments, defined analogously to the Bohr magneton with the mass of the proton replacing that of the electron and equal to about 5·05 × 10-27 joule per tesla; Weiss magneton [named after P. Weiss (see above)], a disused unit (equal to approximately one-fifth of a Bohr magneton) arrived at as the highest common factor of the measured magnetic moments of the atoms of various elements.
At first often regarded as a ‘particle’ or ‘atom’ of magnetism.
1911Sci. Abstr. A. XIV. 191 The author [sc. P. Weiss] is led to postulate the existence of a common constituent of magnetic materials—the elementary magnets of [sic] which he terms magnétons, and which are to be found in the atoms of all magnetic substances. Ibid. 243 (heading) Size of the magneton deduced from the coefficients of magnetisation of solutions of iron salts. 1915Proc. Physical Soc. XXVII. 430 A further comparison with experimental determinations is rendered possible by assuming that the magnetic moment of an electron revolving with the unit of angular momentum is equivalent to 5 magnetons. 1917R. W. Hutchinson Adv. Textbk. Magn. & Electr. II. 313 This fundamental magnet he calls the ‘magneton’. Calculation shows that iron, nickel and magnetite contain 11, 3, and 7 of these magnetons per molecule respectively. 1919Nature 6 Nov. 227/2 The suggestion, first proposed by Weiss, that there exists a natural unit of magnetism called the magneton, analogous in some respects to the atom of electricity, still lacks definite proof. 1923Bohr magneton [see Bohr]. 1927N. V. Sidgwick Electronic Theory of Valency 208 The Bohr magneton..is almost exactly five (4·96) times the Weiss magneton. 1932J. H. Van Vleck Theory Electr. & Magn. Susceptibilities ix. 228 Although many molecules are still found to have moments which are integral multiples of the Weiss magneton within the experimental error, this is probably fortuitous, for there are many reasons for believing the Weiss magneton phenomenon to be spurious. 1935Physical Rev. XLVII. 745/2 Using the value 3/2 for the spin of K39 and 0·0152 for Δν we get 0·39 nuclear Bohr magnetons for the magnetic moment of the K39 nucleus. Ibid. 801/1 We obtain a value of 3·14 nuclear magnetons for the magnetic moment of the Li7 nucleus. 1962H. D. Bush Atomic & Nucl. Physics iii. 60 For all nuclei, including the proton the magnitude of the moment is not an integral multiple of the nuclear magneton. 1973Nature 26 Jan. 239/1 Quantum fluctuations of the electromagnetic field close to the particle [sc. a free electron] imply an apparent increase in its magnetic moment beyond the value of one Bohr magneton implied by the unmodified Dirac theory. |