Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review

Magnetic Moments of the Alkali Metal Atoms

John Bradshaw Taylor

Published Sep 1, 1926• 16 citations
Publisher

Abstract

The work of Stern and Gerlach in which they determined the magnetic moments of certain atoms and at the same time furnished direct evidence of the theory of space quantization, by deflection of rays of the atoms in an inhomogeneous magnetic field, has been repeated for silver atoms. A simplified apparatus is described, using a silver plated tungsten coil as source of atoms, rather than the furnace used by Stern and Gerlach, which gives trouble in outgassing.The magnetic moment of sodium and potassium. The apparatus was further modified for use with the alkali metals by construction of a liquid air cooled target for receiving the atomic rays and a Pyrex glass device for holding the molten metal during evaporation. The images of the rays on the glass target were made visible by immersing in hydrochloric acid gas, which "fixed" them as the opaque and visible chloride. Distinct images of the separated rays resulting from the action of the magnetic field on the oriented atoms have been obtained and are reproduced. Measurements of the separations show that, within the experimental error, sodium and potassium possess magnetic moments equal to one Bohr magneton, in accord with spectroscopic predictions.

DOI
10.1103/physrev.28.576

Related papers

The Magnetic Moment of the Palladium Atom

Albert N. Guthrie, Michael J. Copley

The magnetic moment of the palladium atom has been investigated by the Stern-Gerlach method by evaporating the metal from a tungsten boat resistance furnace through beam forming slits of Pyrex glass and allowing the beam to impinge and condense on a glass plate after passing through an inhomogeneous magnetic field. It was found that images too weak to be detected could be developed satisfactorily by the method used by Stern and Gerlach for silver images. No splitting of the beam of palladium atoms was observed although the same field gave a splitting of 0.04 cm for a beam of atomic hydrogen. This indicates that the palladium atom in its normal state has zero magnetic moment in agreement with spectroscopic results giving for its ground term a $^{1}S$.

Physical Review•Jul 15, 1931•9 citations

The Magnetic Moment of the Hydrogen Atom

T. E. Phipps, John Bradshaw Taylor

The magnetic moment of the hydrogen atom has been investigated by the atomic ray method introduced by Stern and Gerlach. Atomic hydrogen formed in a discharge tube by the method of R. W. Wood was first used. The ray was formed in a special all-glass slit system of three slits sealed to the discharge tube. The ray was detected by the reduction resulting on contact with a target coated with molybdenum trioxide. A sharply defined blue line against a white background was the result. In the magnetic field the ray was separated into two branching rays. There was also evidence of a central underviated ray which is believed to be due to hydrogen active chemically but probably not in the atomic state. From a measurement of the deflection the magnetic moment of the hydrogen atom was calculated to be one Bohr magneton within the limits of experimental error. This result is of interest because of the questions raised by the new quantum mechanics of Heisenberg, Born, and Jordan, and by the spinning electron theory of Uhlenbeck and Goudsmit. Atomic hydrogen formed by the hot filament method of Langmuir was next used. The increased velocity of the atoms in this case resulted in less separation of the ray, but a deflection was distinctly recorded. Finally, the product formed on exposing a mixture of mercury vapor and hydrogen to ultra-violet light was investigated. This is believed by Cario and Franck, Taylor, and others to be atomic hydrogen. Thus far attempts to form a ray which will reduce the target have been unsuccessful. The reasons for this are being investigated.

Physical Review•Feb 1, 1927•100 citations

OBSERVATION OF THE TRANSVERSE STERN–GERLACH EFFECT IN NEUTRAL POTASSIUM

Myer Bloom, Eric Enga, Hin Lew

A successful transverse Stern–Gerlach experiment has been performed, using a beam of neutral potassium atoms and an inhomogeneous time-dependent magnetic field of the form[Formula: see text]A classical analysis of the Stern–Gerlach experiment is given for a rotating inhomogeneous magnetic field. In general, when space quantization is achieved, the spins are quantized along the effective magnetic field in the reference frame rotating with angular velocity ω about the z axis. For ω = 0, the direction of quantization is the z axis (conventional Stern–Gerlach experiment), while at resonance (ω = −γH 0 ) the direction of quantization is the x axis in the rotating reference frame (transverse Stern–Gerlach experiment). The experiment, which was performed at 7.2 Mc, is described in detail.

Canadian Journal of Physics•Apr 1, 1967•26 citations

A Century Ago the Stern–Gerlach Experiment Ruled Unequivocally in Favor of Quantum Mechanics

Břetislav Friedrich

Abstract In 1921, Otto Stern conceived the idea for an experiment that would decide between a classical and a quantum description of atomic behavior, as epitomized by the Bohr–Sommerfeld–Debye model of the atom. This model entailed not only the quantization of the magnitude of the orbital electronic angular momentum but also of the projection of the angular momentum on an external magnetic field – the so‐called space quantization. Stern recognized that space quantization would have observable consequences: namely, that the magnetic dipole moment due to the orbital angular momentum would be space quantized as well, taking two opposite values for atoms whose only unpaired electron has just one quantum of orbital angular momentum. When acted upon by a suitable inhomogeneous magnetic field, a beam of such atoms would be split into two beams consisting of deflected atoms with opposite projections of the orbital angular momentum on the magnetic field. In contradistinction, if atoms behaved classically, the atomic beam would only broaden along the field gradient and have maximum intensity at zero deflection, i. e., where there would be a minimum or no intensity for a beam split due to space quantization. Stern anticipated that, although simple in principle, the experiment would be difficult to carry out – and invited Walther Gerlach to team up with him. Gerlach's realism and experimental skills together with his sometimes stubborn determination to make things work proved invaluable for the success of the Stern–Gerlach experiment (SGE). After a long struggle, Gerlach finally saw, on 8 February 1922, the splitting of a beam of silver atoms in a magnetic field. The absence of the concept of electron spin confused and confounded the interpretation of the SGE, as the silver atoms were, in fact, in a 2S state, with zero orbital and spin angular momentum. However, a key quantum feature whose existence the SGE was designed to test – namely space quantization of electronic angular momentum – was robust enough to transpire independent of whether the electronic angular momentum was orbital or due to spin. The SGE entails other key aspects of quantum mechanics such as quantum measurement, state preparation, coherence, and entanglement. Confronted with the outcome of the SGE, Stern noted: “I still have objections to the idea of beauty of quantum mechanics. But she is correct.”

Israel Journal of Chemistry•Jun 28, 2023•6 citations

Quantisation of angular momenta in atoms

Dzhabrail M Bamatov, Ibragim Musaevich Bamatov, Magomed M. Arsanov

Abstract The aim of the work was to see if the direction of angular momenta in atoms is quantised. In order to do it, a beam of atoms is split, and deflected because of interactions between atomic dipole moments and an externally applied magnetic field. In which case, the angular momenta in atoms is definitively quantised. Firstly, the detector was checked and then the operation of the detector was characterised; secondly, the beam was detected and characterised with residual magnetisation minimised; thirdly, the beam was detected and characterised with magnetic field present. The sample used to determine the magnetic moment was Potassium. The Bohr’s magneton constant value was found to be (9.22±0.7)*10−24 J/T. The answer is lower than the nominal value but lies within the expected error range. This proved the accuracy of the work done and proved the quantisation of the angular momentum, since it proved the presence of magnetic moment.

Journal of Physics Conference Series•Nov 1, 2020•1 citation

Atom interferometer using two Stern-Gerlach magnets

Kenneth H. Rubin, M. Eminyan, F Perales +8 more

An atom interferometer using two Stern-Gerlach magnets as polariser and analyser is described. The interferometer was first operated with a thermal beam of ground state potassium atoms. In that case the beam splitters are two radio-frequency zones within a transverse homogeneous magnetic field building a coherent superposition of Zeeman states. Ramsey fringes are obtained by scanning the RF-frequency through the resonance profile. Pulsing the RF power allows to get the time-of-flight distribution of the beam. Atomic interference fringes (``Stern-Gerlach fringes'') are observed when the magnitude of an inhomogeneous magnetic field located in between the beam splitters is scanned. When the inhomogeneous field is also pulsed, the scalar Bohm-Aharonov effect is observed. The use of metastable helium atoms (He*23S) in place of potassium atoms is proposed. In addition to the usual advantages provided by metastable atoms of high internal energy, this atom offers the specific advantage to behave as an ideal spin-one particle. This allows us to greatly simplify the polarisation scheme of the interferometer. Possible applications involving transversally inhomogeneous magnetic fields are given and limitations due to the finite source size and angular aperture are discussed.

Laser Physics Letters•Mar 9, 2004•12 citations
The work of Stern and Gerlach in which they determined the magnetic moments of certain atoms and at the same time furnished direct evidence of the theory of space quantization, by deflection of rays of the atoms in an inhomogeneous magnetic field, has been repeated for silver atoms. A simplified apparatus is described, using a silver plated tungsten coil as source of atoms, rather than the furnace used by Stern and Gerlach, which gives trouble in outgassing.The magnetic moment of sodium and potassium. The apparatus was further modified for use with the alkali metals by construction of a liquid air cooled target for receiving the atomic rays and a Pyrex glass device for holding the molten metal during evaporation. The images of the rays on the glass target were made visible by immersing in hydrochloric acid gas, which "fixed" them as the opaque and visible chloride. Distinct images of the separated rays resulting from the action of the magnetic field on the oriented atoms have been obtained and are reproduced. Measurements of the separations show that, within the experimental error, sodium and potassium possess magnetic moments equal to one Bohr magneton, in accord with spectroscopic predictions.
The magnetic moment of the palladium atom has been investigated by the Stern-Gerlach method by evaporating the metal from a tungsten boat resistance furnace through beam forming slits of Pyrex glass and allowing the beam to impinge and condense on a glass plate after passing through an inhomogeneous magnetic field. It was found that images too weak to be detected could be developed satisfactorily by the method used by Stern and Gerlach for silver images. No splitting of the beam of palladium atoms was observed although the same field gave a splitting of 0.04 cm for a beam of atomic hydrogen. This indicates that the palladium atom in its normal state has zero magnetic moment in agreement with spectroscopic results giving for its ground term a 1S^{1}S1S.
The magnetic moment of the hydrogen atom has been investigated by the atomic ray method introduced by Stern and Gerlach. Atomic hydrogen formed in a discharge tube by the method of R. W. Wood was first used. The ray was formed in a special all-glass slit system of three slits sealed to the discharge tube. The ray was detected by the reduction resulting on contact with a target coated with molybdenum trioxide. A sharply defined blue line against a white background was the result. In the magnetic field the ray was separated into two branching rays. There was also evidence of a central underviated ray which is believed to be due to hydrogen active chemically but probably not in the atomic state. From a measurement of the deflection the magnetic moment of the hydrogen atom was calculated to be one Bohr magneton within the limits of experimental error. This result is of interest because of the questions raised by the new quantum mechanics of Heisenberg, Born, and Jordan, and by the spinning electron theory of Uhlenbeck and Goudsmit. Atomic hydrogen formed by the hot filament method of Langmuir was next used. The increased velocity of the atoms in this case resulted in less separation of the ray, but a deflection was distinctly recorded. Finally, the product formed on exposing a mixture of mercury vapor and hydrogen to ultra-violet light was investigated. This is believed by Cario and Franck, Taylor, and others to be atomic hydrogen. Thus far attempts to form a ray which will reduce the target have been unsuccessful. The reasons for this are being investigated.
A successful transverse Stern–Gerlach experiment has been performed, using a beam of neutral potassium atoms and an inhomogeneous time-dependent magnetic field of the form[Formula: see text]A classical analysis of the Stern–Gerlach experiment is given for a rotating inhomogeneous magnetic field. In general, when space quantization is achieved, the spins are quantized along the effective magnetic field in the reference frame rotating with angular velocity ω about the z axis. For ω = 0, the direction of quantization is the z axis (conventional Stern–Gerlach experiment), while at resonance (ω = −γH 0 ) the direction of quantization is the x axis in the rotating reference frame (transverse Stern–Gerlach experiment). The experiment, which was performed at 7.2 Mc, is described in detail.
Abstract In 1921, Otto Stern conceived the idea for an experiment that would decide between a classical and a quantum description of atomic behavior, as epitomized by the Bohr–Sommerfeld–Debye model of the atom. This model entailed not only the quantization of the magnitude of the orbital electronic angular momentum but also of the projection of the angular momentum on an external magnetic field – the so‐called space quantization. Stern recognized that space quantization would have observable consequences: namely, that the magnetic dipole moment due to the orbital angular momentum would be space quantized as well, taking two opposite values for atoms whose only unpaired electron has just one quantum of orbital angular momentum. When acted upon by a suitable inhomogeneous magnetic field, a beam of such atoms would be split into two beams consisting of deflected atoms with opposite projections of the orbital angular momentum on the magnetic field. In contradistinction, if atoms behaved classically, the atomic beam would only broaden along the field gradient and have maximum intensity at zero deflection, i. e., where there would be a minimum or no intensity for a beam split due to space quantization. Stern anticipated that, although simple in principle, the experiment would be difficult to carry out – and invited Walther Gerlach to team up with him. Gerlach's realism and experimental skills together with his sometimes stubborn determination to make things work proved invaluable for the success of the Stern–Gerlach experiment (SGE). After a long struggle, Gerlach finally saw, on 8 February 1922, the splitting of a beam of silver atoms in a magnetic field. The absence of the concept of electron spin confused and confounded the interpretation of the SGE, as the silver atoms were, in fact, in a 2S state, with zero orbital and spin angular momentum. However, a key quantum feature whose existence the SGE was designed to test – namely space quantization of electronic angular momentum – was robust enough to transpire independent of whether the electronic angular momentum was orbital or due to spin. The SGE entails other key aspects of quantum mechanics such as quantum measurement, state preparation, coherence, and entanglement. Confronted with the outcome of the SGE, Stern noted: “I still have objections to the idea of beauty of quantum mechanics. But she is correct.”
Abstract The aim of the work was to see if the direction of angular momenta in atoms is quantised. In order to do it, a beam of atoms is split, and deflected because of interactions between atomic dipole moments and an externally applied magnetic field. In which case, the angular momenta in atoms is definitively quantised. Firstly, the detector was checked and then the operation of the detector was characterised; secondly, the beam was detected and characterised with residual magnetisation minimised; thirdly, the beam was detected and characterised with magnetic field present. The sample used to determine the magnetic moment was Potassium. The Bohr’s magneton constant value was found to be (9.22±0.7)*10−24 J/T. The answer is lower than the nominal value but lies within the expected error range. This proved the accuracy of the work done and proved the quantisation of the angular momentum, since it proved the presence of magnetic moment.
An atom interferometer using two Stern-Gerlach magnets as polariser and analyser is described. The interferometer was first operated with a thermal beam of ground state potassium atoms. In that case the beam splitters are two radio-frequency zones within a transverse homogeneous magnetic field building a coherent superposition of Zeeman states. Ramsey fringes are obtained by scanning the RF-frequency through the resonance profile. Pulsing the RF power allows to get the time-of-flight distribution of the beam. Atomic interference fringes (``Stern-Gerlach fringes'') are observed when the magnitude of an inhomogeneous magnetic field located in between the beam splitters is scanned. When the inhomogeneous field is also pulsed, the scalar Bohm-Aharonov effect is observed. The use of metastable helium atoms (He*23S) in place of potassium atoms is proposed. In addition to the usual advantages provided by metastable atoms of high internal energy, this atom offers the specific advantage to behave as an ideal spin-one particle. This allows us to greatly simplify the polarisation scheme of the interferometer. Possible applications involving transversally inhomogeneous magnetic fields are given and limitations due to the finite source size and angular aperture are discussed.