Lines positions temperature dependence

Fig. 7.15 (continued) (c) Superposed experimental and calculated 30.41 MHz (7 T) 15N NMR spectra of 15N enriched DPP at different temperatures and deuterium fractions xd in the mobile sites. The four sharp lines with temperature dependent positions stem from a small quantity of 15N labeled tetramethyltertraaza-[14]annulene reference in a separate capsule (Klein, O., Limbach, H. H., et al. J. Am. Chem. Soc. 126, 11718 (2004))... 

If the miscibility gap of Pri+xl2 is temperature dependent (which they usually are), then Prl2 could be a line phase at, say, ambient temperature, i.e., x = 0. Hence, on quenching or when the annealing process progresses, the metastable i+xh phase must release praseodymium metal. This surplus praseodymium metal can be released from both the 3 a (heavily under-occupied) and 3 b (fully occupied) positions combined with site changes from 3 b to 3 a, or not. These... 

Since both the temperature dependence of the characteristic ratio and that of the density are known, the prediction of the scaling model for the temperature dependence of the tube diameter can be calculated using Eq. (53) the exponent a = 2.2 is known from the measurement of the -dependence. The solid line in Fig. 30 represents this prediction. The predicted temperature coefficient 0.67 + 0.1 x 10-3 K-1 differs from the measured value of 1.2 + 0.1 x 10-3 K-1. The discrepancy between the two values appears to be beyond the error bounds. Apparently, the scaling model, which covers only geometrical relations, is not in a position to simultaneously describe the dependences of the entanglement distance on the volume fraction or the flexibility. This may suggest that collective dynamic processes could also be responsible for the formation of the localization tube in addition to the purely geometric interactions. 

We will first describe the results obtained for n-type GaAs doped with silicon and then those on p-type GaAs and InP, trying to show how the spectroscopic results correlate with the electrical measurements to provide a consistent picture of the neutralization of dopants by hydrogen in III-V semiconductors. After considerations on the temperature dependence of the widths and positions of the H-related lines, we will discuss the occurrence and origin of other vibration lines associated also with hydrogen in as grown bulk and epitaxial III-V compounds. 

Clearly, the solutions of nonlinear gap equations are not unique. In numerical calculations we separated the physical solutions by observing the sign of 4>q and that of the effective potential at the stationary point W//( o)- The temperature dependence of these two quantities are presented in Fig. 2. It is seen that 4>q (solid line) is positive in the large range of r and goes to zero when r is close to r = 1. Similarly, the depth of the effective potential at the stationary point, Veff(4>o), becomes shallow when r —> 1 and vanishes at T = Tc. 

The temperature dependent line shape of racemic PBG-yd2 is shown in Fig. 34 together with those of PBLG-yd2. The line shapes at room temperature appear to be the rigid state powder pattern, showing the absence of the large amplitude motion in the y position. The signal intensity of the... 

Figure 20 Temperature dependence of the a-relaxation time scale for PB. The time is defined as the time it takes for the incoherent (circles) or coherent (squares) intermediate scattering function at a momentum transfer given by the position of the amorphous halo (q — 1.4A-1) to decay to a value of 0.3. The full line is a fit using a VF law with the Vogel-Fulcher temperature T0 fixed to a value obtained from the temperature dependence of the dielectric a relaxation in PB. The dashed line is a superposition of two Arrhenius laws (see text).

Table I lists the comparative parameters for the various indochinite spectra. Two methods were used in preparing these samples. The first two samples listed were prepared by grinding the indochinite specimen and binding the powder with water glass. The other samples were sliced with a diamond saw. The two spectral lines are given with their position, width, height, and area. The quadrupole splitting and isomer shift are listed in the columns labeled QS and IS. (The isomer shift is really a combination of isomer shift and temperature-dependent shift, and the values are relative to iron in palladium.) The raw data points were fitted with a two-peak Lorentzian using an IBM 7094 least-squares fit.

Fig. 2 Temperature dependence of the - 1/2 -0-+ 1/2 NMR spectrum in the region of the PE-FE phase transition for D-RADP-20 (Bo c). The positive frequency shift from the pure PE line to the pure FE line amounts to 8 kHz. The change in the line shape clearly indicates the coexistence of both phase states over a wide temperature range [17]...

The basic features of the Mb111 (Ns) spectrum are similar to those of cyanoferrimyoglobin (Fig. 14). Only one set of hyperfine-shifted resonances is observed, but the hyperfine shifts are larger and the lines broader than in MbmCN. Furthermore the temperature dependences of the resonances positions show drastic deviations from Curie s law (Eq. 4). Similar data were also obtained for azidoporphyrin-iron(III) complexes in pyridine solution 116). 

With the PMK ligand a CoCu derivative has been obtained [7] (Fig. 6.7). From the temperature dependence of the shifts (and magnetic susceptibility measurements in solution), the value of J appears to be positive and much smaller than kT [13]. As expected, the hyperfine shifts are the sum of those of the CuZn and ZnCo systems for each proton (Table 6.2). The NMR lines of the copper domain are now quite sharp, even sharper than those of the cobalt domain (Fig. 6.7). Qualitatively, the data can be accounted for if xs of copper is sizably reduced and approaches that of cobalt (and thus the Redfield limit is reached). 

The CP MAS DD 13C NMR spectrum at 23 °C is shown in Fig. 81. The 166.9, 136.8, 127.3 and 17.4 ppm lines correspond to the C = 0 carbons, unprotonated and protonated aromatic carbons, and methyl carbons, respectively. The set of lines at 46.3, 40.7, 32.3 and 27.4 ppm correspond to aliphatic CH and CH2 carbons. The temperature dependence of the t /2 values of these aliphatic carbons is shown in Fig. 82. The carbons associated with the 40.7 and 43.6 ppm lines, whose onset of motions occurs above 100 °C, should correspond to the CH2 carbons in a position with respect to the amide group. Consequently, the 27.4 and 32.3 ppm lines, associated with carbon atoms which undergo motions at temperature equal or higher than 20 °C, should correspond to the central CH2 carbons of the aliphatic sequence. 

Fig. 1. Temperature dependence of the homogeneous width y (a) and position 8 (b) (in u>d units) of a zero-phonon line in the Debye model for different values of the interaction parameter wcx/w indicated in the right-side boxes. The instability limit corresponds to wcr/w = 1.

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