Order of reflection

Line Order of reflection Angle of reflection dm Estimated intensity... 

Fig. 2. Amplitude curves for eight orders of reflection from (4 4 o) of sodalite as a function of the sodium parameter u.

The factor n is required by the experimental conditions, under which the amount of incident radiation intercepted by the face of the crystal increases linearly with the order of reflection. The temperature factor corresponds to an estimated characteristic temperature of about 530° The /0-values used are those ofPauling and Sherman1). It is seen that the observed intensity relations (800) (600)... 

Fig. 1. Calculated intensities for various orders of reflection from (100) of sulvanite...

If, moreover, we consider a set of peaks with the index (h) counting the orders of reflections, then the effects of size and instrumental broadening are readily eliminated... 

Thus the only systematic absences caused by a twofold screw axis are the odd orders of reflection from the plane perpendicular to the screw axis. 

In a similar way, in a crystal exhibiting a threefold screw axis 3X or 32, identical atoms are repeated on planes spaced one-third the length of the axis therefore the reflections from the plane normal to the screw axis would, by themselves, appear to indicate a repeat distance only one-third the true axial length. The first of these reflections w ould be the third-order reflection in reference to the true repeat distance, wrhile the second would be actually the sixth-order reflection. In other words, a threefold screwr axis 3X or 32 causes the absence of the first and second orders of reflection from the plane perpendicular to the screw axis, as... 

Electron density maps. We have seen that a diffracted X-ray beam may be regarded as a reflection from a set of parallel planes of lattice points, and that the intensities of the different orders of reflection from this set of planes depend on the distribution of atoms between one plane and the next. Consequently a synthesis of all the orders of... 

A one-dimensional Fourier synthesis can be used for the direct determination of atomic parameters along any crystal axis, provided that the phase angles ct for the various orders of reflection are known. For an example, consider the structure of sodium nitrite, already described in Chapter IX. It is body-centred, hence only even orders of 00/ appear their structure amplitudes are 8, 15, 10, 2, and 7 for 002, 004, etc., respectively. 

The domain spacing obtained by Hamley et al. (1997a) and Ryan et al. (1995) increased discontinuously upon crystallization, as indicated by the shift of the principal peak position, q, to lower q, as apparent in Fig. 5.3. Here q = AnsinOIX where 20 is the scattering angle and X is the X-ray wavelength. The SAXS profiles from the crystallized diblocks were shown to correspond to the sum of scattering from block copolymer lamellae, with up to four orders of reflection, plus a broad... 

Fig. 5.17 SAXS patterns for PEQwPBO.w showing (a) the ordered melt structure (T = 90 °C) (b) a metastable structure at T = 42 °C (c) the equilibrium once-folded structure grown at T - 50°C by a self-seeding process (Ryan et al. 1997). Numbers indicate the order of reflection from a lamellar structure and the arrow indicates the position of the peak in the ordered melt. The calculated repeat lengths for possible molecular conformations are indicated.

Fig. 2.3. Five orders of reflection in a thin film results also show the presence of the two most X-ray diffraction scan, indicating the high level common polymorphs of pentacene, the bulk-of crystallinity often present in pentacene thin like phase and the thin-film phase [25]. films deposited on different dielectrics. These...

The integer n is often called the order of reflection and the angle 6 the... 

Fock 18, 19 hamiltonian 16 kinetic energy 16 Laplacian 85 logical 86 mathematical 84 matrix element of 16 momentum 16 nabla 85 symmetry 27, 38 optical rotation 33 optical rotatory power 33 orbital energy 18 order of reaction 55 order of reflection 36 order parameters 36 oscillator strength 33 osmole 51... 

Element Transition Wavelength, X (in first order of reflection) Remarks... 

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