lamellarspectrum

Lamellarspectrum is a term used in materials science and soft matter physics to denote the spectral pattern associated with lamellar, or layered, structures when probed by scattering techniques such as small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), or small-angle neutron scattering (SANS). In a well-ordered lamellar phase, the electron density varies periodically in one direction with repeat distance d, producing a series of Bragg reflections at scattering vectors qn = 2π n / d for integer n.

Its appearance is a set of discrete peaks along the scattering vector, with peak positions proportional to the order n and relative intensities governed by the layer structure factor and stack coherence. The fundamental peak corresponds to the repeat distance; higher-order peaks indicate a higher degree of lamellar order. The width of peaks provides a measure of the finite stack size and the correlation length along the normal to the layers. In oriented or anisotropic samples, peaks align along specific directions; in isotropic systems, peaks form Debye–Scherrer rings around the beam.

Lamellarspectrum arises in a variety of materials, including block copolymers forming lamellae, lipid bilayer systems, smectic liquid crystals, clays and other layered inorganic materials, and some nanoplatelet assemblies. Interference from disorder, tilt, or coexisting morphologies can blur or alter the peaks, making interpretation challenging. Analysis often requires modeling the form factor and structure factor and may benefit from complementary techniques such as electron microscopy.

See also lamellar phase, Bragg diffraction, SAXS, SANS.