Nuclear effects

The methods listed thus far can be used for the reliable prediction of NMR chemical shifts for small organic compounds in the gas phase, which are often reasonably close to the liquid-phase results. Heavy elements, such as transition metals and lanthanides, present a much more dilficult problem. Mass defect and spin-coupling terms have been found to be significant for the description of the NMR shielding tensors for these elements. Since NMR is a nuclear effect, core potentials should not be used. 

Nadal A, Diaz M, Valverde MA (2001) The estrogen trinity membrane, cytosolic, and nuclear effects. News Physiol Sci 16 251-255... 

Refractory materials in primitive meteorites were investigated first as they have the best chance of escaping homogenization in the early solar system. Inclusions in C3 carbonaceous chondrites exhibit widespread anomalies for oxygen and the iron group elements. Only a few members, dubbed FUN (for Fractionated and Unknown Nuclear effects), also display anomalous compositions for the heavy elements. Anomalies in inclusions have generally been connected with explosive or supernova nucleosynthesis. 

Fig. 6 compares the nuclearity effect on the redox potentials [19,31,63] of hydrated Ag+ clusters E°(Ag /Ag )aq together with the effect on ionization potentials IPg (Ag ) of bare silver clusters in the gas phase [67,68]. The asymptotic value of the redox potential is reached at the nuclearity around n = 500 (diameter == 2 nm), which thus represents, for the system, the transition between the mesoscopic and the macroscopic phase of the bulk metal. The density of values available so far is not sufficient to prove the existence of odd-even oscillations as for IPg. However, it is obvious from this figure that the variation of E° and IPg do exhibit opposite trends vs. n, for the solution (Table 5) and the gas phase, respectively. The difference between ionization potentials of bare and solvated clusters decreases with increasing n as which corresponds fairly well to the solvation free energy of the cation deduced from the Born solvation model [45] (for the single atom, the difference of 5 eV represents the solvation energy of the silver cation) [31]. 

In the absence of dynamic and static disorder, all partially filled band systems would exhibit coherent transport over long distances. With static and dynamic disorder, the modulation of the simple molecular orbital or band structure by nuclear effects entirely dominates transport. This is clear both in the Kubo linear response formulation of conductivity and in the Marcus-Hush-Jortner formulation of ET rates. The DNA systems are remarkable for the different kinds of disorder they exhibit in addition to the ordinary static and dynamic disorder expected in any soft material, DNA has the covalent disorder arising from the choice of A, T, G, or C at each substitution base site along the backbone. Additionally, DNA has the characteristic orientational and metric (helicoidal) disorder parameters arising from the fundamental motif of electron motion along the r-stack. 

For an elementary proton r )p = 0, g = 2, and only the first term in the square brackets survives. This term leads to the well known local Darwin term in the electron-nuclear effective potential (see, e.g., [1]) and generates the contribution proportional to the factor Sio in (3.4). As was pointed out in [2], in addition to this correction, there exists an additional contribution of the same order produced by the term proportional to the anomalous magnetic moment in (6.6). 

A breakthrough was achieved a few years ago when it was realized that an anal dic calculation of the deuterium recoil, structure and polarizability corrections is possible in the zero range approximation [76, 77]. An analytic result for the difference in (12.29), obtained as a result of a nice calculation in [77], is numerically equal 44 kHz, and within the accuracy of the zero range approximation perfectly explains the difference between the experimental result and the sum of the nonrecoil corrections. More accurate calculations of the nuclear effects in the deuterium hyperfine structure beyond the zero range approximation are feasible, and the theory of recoil and nuclear corrections was later improved in a number of papers [78, 79, 80, 81, 82]. Comparison of the results of these works with the experimental data on the deuterium hyperfine splitting may be used as a test of the deuteron models and state of the art of the nuclear calculations. 

This splitting in the energy level is similar to the Zeeman effect that causes separation of electronic states in a magnetic field. It is sometimes referred to in NMR as the Zeeman nuclear effect. 

Present address Nuclear Effects Laboratory, Edgewood Arsenal, Md. 21010. 

To elucidate some interesting differences between particles that were altered significantly by the thermal history to which they had been subjected and particles that were relatively unaltered, we present data obtained by personnel at the Nuclear Effects Laboratory, who analyzed prompt fallout from the 5-megaton surface coral explosion, Tewa. These samples were obtained within 16 km. of ground zero. 

When SP [T] = SP"[0] (condition 2), AS°[T] can be expressed as v (SP [T] — Sp"[0]) that is, in terms of the observed quantities. We use the difference (Sp [T] — SP"[0]) as the absolute value of the entropy, which is equivalent to assigning the value of zero to SP"[0]. The two effects for which this assignment is valid are (1) the nuclear effects including those of nuclear spin, provided that the isothermal change of state does not involve a nuclear reaction and (2) the isotopic effects, provided there is no change in the isotopic composition of the substances. 

Palladium is a metal of particular interest in this respect because it has an unusually high solubility for H and because it is the principal metal in which chemically assisted nuclear effects have been reported (Fleischmann and Pons, 1989). For the evolution on Pd of H2from LiOH and LiOD-containing solutions,... 

Membrane-containing fractions displaying T3-binding activities have been detected in a variety of cell types [13-16], Rat liver [15] and erythrocyte [16] plasma membranes, for instance, contain T4- and T3-binding sites with affinities ranging from 1 to 10 x 10 10 M for T3. It is not clear whether the function of these sites is related to the transport of thyroid hormones from the blood to the cell or if they represent receptors responsible for non-nuclear effects of thyroid hormones [17,18]. 

Perhaps a problem more important for applications is to eliminate the nuclear effects and to test the bound state QED precisely or use the bound state QED for the determination of some fundamental physical constants. There are a few ways to manage this problem [11] and to expand the accuracy of the tests of bound state QED beyond a level of our knowledge of the nuclear structure effects. 

The nuclear effects (both for the hyperline structure and the Lamb shift) are a result of short-distance contributions and in the leading order are proportional to the Schrodinger-Coulomb wave function at the origin,... 

There is a kind of atom where the nuclear effects are very large - exotic atoms, containing hadrons, i.e. particles that can interact strongly pions, antiprotons, kaons etc. In such atoms any advanced high-accurate QED theory is not necessary and a goal to study such atoms is to measure these nuclear parameters. An important feature of any spectroscopic measurement is its high accuracy in respect to non-spectroscopic methods. That is very important for exotic atoms, because some, like e.g. pionium (7r+7r -system or bound 7rp-system), are available in very small quantities (a few hundreds) [35],... 

In order to extract the QED or nuclear effects from the 1S-2S frequency, a second frequency must be known. The present uncertainty in the Lamb shift and Rydberg constant is determined by the accuracy of such a measurement. The most precise measurements have been made on transitions from 2S to higher levels in a super-thermal beam of metastable 2S atoms [19]. As will be described, ultracold hydrogen offers possibilities for significant improvements. 

Abstract. The usefulness of study of hyperfine splitting in the hydrogen atom is limited on a level of 10 ppm by our knowledge of the proton structure. One way to go beyond 10 ppm is to study a specific difference of the hyperfine structure intervals 8Au2 — Avi. Nuclear effects for axe not important this difference and it is of use to study higher-order QED corrections. 

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