Neutron scattering data

There are many different data analysis schemes to estimate the structure and molecular parameters of polymers from the neutron scattering data. Herein, we will present several connnon methods for characterizing the scattering profiles, depending only on the applicable q range. These methods, which were derived based on different assumptions, have... 

In polymer solutions or blends, one of the most important thennodynamic parameters that can be calculated from the (neutron) scattering data is the enthalpic interaction parameter x between the components. Based on the Flory-Huggins theory [4T, 42], the scattering intensity from a polymer in a solution can be expressed as... 

More recently, simulation studies focused on surface melting [198] and on the molecular-scale growth kinetics and its anisotropy at ice-water interfaces [199-204]. Essmann and Geiger [202] compared the simulated structure of vapor-deposited amorphous ice with neutron scattering data and found that the simulated structure is between the structures of high and low density amorphous ice. Nada and Furukawa [204] observed different growth mechanisms for different surfaces, namely layer-by-layer growth kinetics for the basal face and what the authors call a collected-molecule process for the prismatic system. 

Fig. 6.5. Coherent structure function S(q) in absolute units in comparison to amorphous cell simulations [194] and neutron scattering data [185]...

Fig. 53. Small-angle neutron scattering data from the 12-arm polystyrene star PS120A (Mw = 1.49 x 105) where the 11 deuterated arms were matched by the solvent THF. In order to demonstrate the asymptotic Q behavior, the data are plotted in a generalized Kratky representation (Iq01 vs. Q with a = 1.5 and 5/3). The solid line marks the high Q-plateau. (Reprinted with permission from [149]. Copyright 1989 American Chemical Society, Washington)...

Beaucage [83] showed that it could be possible to get branching information for polymers using this approach. In Figure 14, where neutron scattering data for branched polystyrene is fit to the unified equation [83,107,110-112], it was shown that it is possible to calculate the parameters dmin and c, from such a fit [83]. These model branched polystyrene samples were synthesized by using divinyl benzene (10%) as a comonomer, to obtain controlled levels of branching but where the placement is random. 

Figure 14 Neutron scattering data from branched polystyrene fit to the unified equation [83]. Reprinted with permission from Beaucage [83]. Copyright 2004, American Physical Society. (Both the branched PS fractions were synthesized using divinyl benzene as a comonomer. Fraction F2 has a weight average molar mass of 18 x 108 g/mol and fraction F5 has a weight average molar mass of 2.0 x 108 g/mol, see Ref. 147.)...

A similar analysis in terms of conformational dynamics can be performed as well for the interpretation of neutron scattering data in the picosecond time window159 and dielectric data.156 How do these findings then... 

Fig. 3. A comparison, of neutron scattering data from the experiments of Narten (o) and of Powles (----) (from Ref. 19>)...

Papoular, R. J. and Gillon, B., in Neutron Scattering Data Analysis, M. W. Johnson (ed.), Inst. Phys. Conf. Ser. 107, Bristol (1990b), p. 101. 

Wilson RM, I-oveday JS, Nehnes RJ, Klotz S, Marshall WG (1995) Nuclear Instmm Methods Phys Res Sect A Accelerators Spectrometers Detectors and Associated Equipment 354(1) 145. Third Workshop on Neutron Scattering Data Analysis (WONSDA 94), Chilton, England, 13-15 Apr 1994... 

The melting temperatures for the thirty-one elements, whose inelastic neutron scattering data are available, were calculated and compared against the observed melting temperatures as shown in Table 1. In this calculation, the thirty-one elements are sorted into three groups according to their crystal structure type. Different correction factor, A,... 

Fig. 8. Difference in the inelastic neutron scattering data between LaFe4Sb 2 and CeFe4Sb 2 vs. energy loss (Keppens et al., 1998). CeFe4Sbi2 was used as a reference compound since the neutron scattering cross section of Ce is much smaller than that of La. The difference spectra therefore reflect the vibrational density of states (DOS) associated with the La atoms. The peak at 7 meV (78 K) corresponds to the quasi-localized La mode. The second broader peak at about 15 meV corresponds to the hybridization of La and Sb vibrational modes. Both peaks can be accounted for using lattice dynamic models based on first-principles calculations (Feldman et al., 2000).

Table 1 Inelastic neutron scattering data for H2 adsorbed by Raney nickel...

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