Electronic Structure of Alkali Metals. I. Fermi Surfaces of Sodium and Potassium

1976 ◽  
Vol 40 (1) ◽  
pp. 100-106 ◽  
Author(s):  
Koji Takano ◽  
Ikuyo Shiozaki
Keyword(s):  
Electronic Structure ◽  
Alkali Metals ◽  
Fermi Surfaces ◽  
Sodium And Potassium

The de Haas–van Alphen effect in alkali metals

1964 ◽  
Vol 281 (1384) ◽  
pp. 62-91 ◽  
Keyword(s):  
Fermi Surface ◽  
Field Dependence ◽  
Alkali Metals ◽  
Spherical Shape ◽  
Orientation Dependence ◽  
Sodium Potassium ◽  
Fermi Surfaces ◽  
Fixed Orientation ◽  
Absolute Amplitude ◽  
Structure Calculations

A new method for studying the de Haas–van Alphen effect in steady magnetic fields has been developed in which the field is modulated at frequency ω and a signal at frequency 2 ω is generated in a pick-up coil round the specimen because of the non-linear field dependence of magnetization. The rectified 2 ω signal is proportional to d 2 M /dH 2 and so shows de Haas–van Alphen oscillations either when H is varied for fixed orientation or when the orientation is varied in fixed H if the Fermi surface is anisotropic. Because the phase of oscillation is very high (of order 10 4 π ) even very slight anisotropy will produce a few oscillations when the orientation is varied and the method is therefore particularly sensitive for studying very nearly spherical Fermi surfaces. From the oscillations with H , values of the frequency F were found for sodium, potassium, rubidium and caesium which were close to those predicted for a free-electron sphere containing 1 electron per atom, though some small systematic deviations of order ½ % were observed which may be significant. From detailed study of the oscillations produced by rotation of single crystals in fixed H it was found possible to describe the orientation dependence of F (proportional to the area of cross-section of the Fermi surface) for potassium and rubidium consistently by a series of cubic harmonics and hence to deduce the small departures of the Fermi surfaces from spherical shape. The deviations from a sphere were found to be of the order of 1 part in 10 3 for potassium and a little less than 1 part in 10 2 for rubidium; these deviations are compared with those predicted by band structure calculations. Preliminary results for sodium suggest that it is appreciably less anisotropic than potassium. Some results are also reported on the temperature and field dependence and the absolute amplitude of the de Haas-van Alphen effect, and it is also shown how the effect can be used to measure very small variations of field with position.

scholarly journals Emission of Noble Gases Binary Mixtures under Excitation by the Products of the 6Li (n, α)3 H Nuclear Reaction

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Kuanysh Samarkhanov ◽  
Mendykhan Khasenov ◽  
Erlan Batyrbekov ◽  
Inesh Kenzhina ◽  
Yerzhan Sapatayev ◽  
...  
Keyword(s):  
Nuclear Reaction ◽  
Nuclear Energy ◽  
Alkali Metals ◽  
Nuclear Reactor ◽  
Noble Gases ◽  
Noble Gas ◽  
Direct Conversion ◽  
Reaction Products ◽  
Gas Molecules ◽  
Sodium And Potassium

The luminescence of Kr-Xe, Ar-Kr, and Ar-Xe mixtures was studied in the spectral range 300–970 nm when excited by 6Li (n, α)3 H nuclear reaction products in the core of a nuclear reactor. Lithium was deposited on walls of experimental cell in the form of a capillary-porous structure, which made it possible to measure up to a temperature of 730 K. The temperature dependence of the radiation intensity of noble gas atoms, alkali metals, and heteronuclear ionic noble gas molecules was studied. Also, as in the case of single-component gases, the appearance of lithium lines and impurities of sodium and potassium is associated with vaporization during the release of nuclear reaction products from the lithium layer. The excitation of lithium atoms occurs mainly as a result of the Penning process of lithium atoms on noble gas atoms in the 1s states and subsequent ion-molecular reactions. Simultaneous radiation at transitions of atoms of noble gases and lithium, heteronuclear ion molecules of noble gases allows us to increase the efficiency of direct conversion of nuclear energy into light.

Fermi surfaces and electronic structure of the Heusler alloy Co2TiSn

2006 ◽  
Vol 18 (10) ◽  
pp. 2897-2903 ◽  
Author(s):  
M C Hickey ◽  
A Husmann ◽  
S N Holmes ◽  
G A C Jones
Keyword(s):  
Electronic Structure ◽  
Heusler Alloy ◽  
Fermi Surfaces

Electronic structure, magnetism, and Fermi surfaces of Gd and Tb

1994 ◽  
Vol 50 (8) ◽  
pp. 5147-5154 ◽  
Author(s):  
R. Ahuja ◽  
S. Auluck ◽  
B. Johansson ◽  
M. S. S. Brooks
Keyword(s):  
Electronic Structure ◽  
Fermi Surfaces

Artificial Transmembrane Channels for Sodium and Potassium

2002 ◽  
Vol 85 (3) ◽  
pp. 219-241 ◽  
Author(s):  
Peter J. Cragg
Keyword(s):  
Ion Transport ◽  
Alkali Metals ◽  
Structural Features ◽  
Artificial System ◽  
Ion Specificity ◽  
Ion Concentrations ◽  
Transmembrane Channels ◽  
Essential Function ◽  
Membrane Spanning ◽  
Sodium And Potassium

Transport of alkali metals, particularly sodium and potassium, across cell membranes is an essential function performed by special proteins that enable cells to regulate inter- and extracellular ion concentrations with exceptional selectivity. The importance of these channel-forming proteins has led to researchers emulating of their structural features: an ion-specific filter and conduction at rates up to 108 ions per second. Synthetic helical and cyclic polypeptides form channels, however, the specificity of ion transport is often low. Ion-specific macrocycles have been used as filters from which membrane-spanning derivatives have been prepared. Success has been limited as many compounds act as ion carriers rather than forming transmembrane channels. Surfactant compounds also allow ions to cross membranes but any specificity is serendipitous. Overall it seems possible to mimic either ion specificity or efficient transmembrane ion transport. The goal for the future will be to combine both characteristics in one artificial system.

Ion pairs formed by alkali metals. Part 1.—Complexes of lithium, sodium and potassium with 4-nitropyridine

1975 ◽  
Vol 71 (0) ◽  
pp. 1829-1838 ◽  
Author(s):  
Pietro Cremaschi ◽  
Aldo Gamba ◽  
Gabriele Morosi ◽  
Cesare Oliva ◽  
Massimo Simonetta
Keyword(s):  
Alkali Metals ◽  
Ion Pairs ◽  
Sodium And Potassium

Electronic Structure and the Fermi Surfaces of Antiferromagnetic NdB6

1993 ◽  
Vol 62 (1) ◽  
pp. 205-214 ◽  
Author(s):  
Yasunori Kubo ◽  
Setsuro Asano ◽  
Hisatomo Harima ◽  
Akira Yanase
Keyword(s):  
Electronic Structure ◽  
Fermi Surfaces
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