Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

F waves

When M is an atom the total change in angular momentum for the process M + /zv M+ + e must obey the electric dipole selection mle Af = 1 (see Equation 7.21), but the photoelectron can take away any amount of momentum. If, for example, the electron removed is from a d orbital ( = 2) of M it carries away one or three quanta of angular momentum depending on whether Af = — 1 or +1, respectively. The wave function of a free electron can be described, in general, as a mixture of x, p, d,f,... wave functions but, in this case, the ejected electron has just p and/ character. [Pg.296]

F = wave or pulse frequency Tj = kinematic viscosity in ftVs... [Pg.951]

Symmetry of superconducting state. No Hebel-Slichter coherence peak was observed in either k -(ET)2Cu(NCS)2 or c-(ET)2Cu[N(CN)2]Br in NMR measurements, ruling out a BCS s-wave state. The symmetry of the superconducting state of c-(ET)2Cu(NCS)2 had been controversially described as normal BCS-type or non-BCS type however, scanning tunneling spectroscopy showed f-wave symmetry with line nodes along the direction near ti/4 from k - and Kc-axes [228, 229], and thermal conductivity measurements were consistent with this result [230]. c-(ET)2Cu [N(CN)2]Br showed the same symmetry [231]. [Pg.96]

All considerations in the following development of this chapter answer this question affirmatively. This affirmative answer means that the light actinides (up to Pu) constitute a new kind of transition series, as yet unknown, where the 5 f wave functions play the role that d-wave functions have in the d-transition metal series. After Pu (with Am (and Cm) occupying an intermediate and particularly interesting position) heavy actinides may on the contrary be described as a new lanthanide-type series. [Pg.13]

The characteristic structure of the actinide spectra is mainly determined by the special properties of the 5 f wave functions these, in turn, arise from the special nature of the 5 f effective potential-energy function Ueff (5f). Uetf describes the effect on the 5 f electrons of the attraction by the nucleus as well as of all the interactions with other electrons. It contains also a centrifugal term, 1(1 -I- l)/2 r, of particular importance for the properties of 5f wave functions, the effect of which will be illustrated later in more detail. [Pg.17]

Spatial extension, as expressed by the expectation value (r), is roughly comparable for 4 f and 5 f wave functions (Figs. 7 and 8). However, the many-electron wave functions resulting from the solution of the relativistic Dirac equation may also be used to calculate a number of physically interesting quantities, i.e. expectation values of observable... [Pg.19]

A very relevant representation of atomic 5 f wave functions is given by Freeman and Koelling ... [Pg.20]

For the light actinides from a) and b) qualitative consequences may be drawn. It follows, from f-f overlapping, that the atomic 5 f wave functions will broaden into 5 f bands when building the metal. Moreover, since the 5 f, 6 d and 7 s energy eigenvalues are very close (see Sect. A.II) the 5 f band will hybridize strongly with the 5 d and 7 s bands. [Pg.23]

The f-f overlapping in light actinides may cause broadening of the 5 f wave functions into 5 f bands. On the other hand, from Am on, this overlapping having decreased, this effect occurs much less. It follows that physical properties which depend from 5f orbitals may be better understood, in one case, in the band Umit, in the other case, in the atomic limit. [Pg.24]

We have discussed and distinguished two limiting cases for 5 f wave functions ... [Pg.34]

As noted by Hill himself the weakness of the Hill plots comes from the crude assumption that direct overlap of 5 f wave functions is the only parameter governing the 5 f bandwidth. [Pg.50]

Finally, in Chap. F, a description of the most refined theoretical methods, as employed in actinides, is given, and its results for actinide solids are discussed. In the first part of the chapter, the author starts discussing actinides by presenting... the zirconium atom a striking beginning, purposely introduced in order to show the transition metal properties of 5 f wave functions. [Pg.54]

For a given angular momentum (d or f) the bands broaden as the principle quantum number increases. Thus 5d bands are much broader than the 3d bands. The reason for this is that states with principle quantum number n +1 must have an additional node (the orthogonality node) to the states with principle quantum number n. This pushes the wave function, relatively, further from the nucleus. Hence the 5 f wave functions are more extended than 4f wave functions which leads to their tendency to form bands. [Pg.268]

The actinide solid state properties are to a large extent based on the properties of the 5f wave-functions. Central to the actinide solid state research has been the co-existence of evidence and of concepts pointing clearly to the recognition of light actinides as being elements in which a metallic bond is enhanced by the overlapping of 5 f wave-functions. The narrow band, itinerant character of the 5 fs is similar to the one d-shells have hence, the classification of these elements as 5 f-transition metals. [Pg.295]

A 1.547 medium is often used for examination of quartz by dispersion staining. This medium will show the F wave length color golden magenta (486.0 nanometers) for epsilon and the C wave length color blue green (656.0 nanometers) for omega as viewed with central stop. [Pg.37]

A 46-year-old man chronically abused heroin through inhalation and developed a gait disorder with paresthesia of the legs, incontinence, and impotence. MRI scans showed bilateral subcortical lesions and bilateral signal abnormalities in the corticospinal tract and posterior columns. Motor evoked potentials were slow, with prolonged F wave latency, which is evidence of peripheral nerve disease. Multivitamins and high doses of prednisone did not produce benefit. [Pg.545]

The magnetic interaction between the ions in the magnetic metals for example, can then be considered as carried by the conduction electrons in the well known Rudermann-Kittel-Kasuya-Yoshida (1 ) interaction. The physical origin of this interaction is a point like polarization of the conduction electrons (CE), at the atomic sites, by the magnetic moments of the f electrons, resulting in an oscillation of the spin density of the CE. The point like approximation is useful because the maxima of the f wave functions are found well inside the atomic core, in radii smaller than 0.7 atomic units. This polarization is carried from ion to ion by the generated polarization oscillation of the conduction electron spins, which has a wave length = 27r/e (C =... [Pg.246]

As it was presented in our studies of the f bands, in terms of the actual f-wave functions in the atomic and in the condensed matter case we found that the width of the band is related... [Pg.255]


See other pages where F waves is mentioned: [Pg.59]    [Pg.231]    [Pg.117]    [Pg.108]    [Pg.56]    [Pg.59]    [Pg.30]    [Pg.19]    [Pg.19]    [Pg.23]    [Pg.23]    [Pg.27]    [Pg.48]    [Pg.51]    [Pg.52]    [Pg.296]    [Pg.135]    [Pg.80]    [Pg.780]    [Pg.117]    [Pg.185]    [Pg.781]    [Pg.168]    [Pg.108]    [Pg.63]    [Pg.19]    [Pg.780]    [Pg.248]    [Pg.248]    [Pg.249]    [Pg.252]    [Pg.253]   
See also in sourсe #XX -- [ Pg.90 , Pg.91 ]




SEARCH



Controlling Surface Waves on Finite Arrays of Active Elements With FSS Groundplane

Controlling Surface Waves on Finite FSS Groundplanes

Surface Wave Radiation from an FSS

© 2024 chempedia.info