X-ray scattering from a discrete helix with cumulative angular and translational disorders

Area of Science:

• Crystallography
• Materials Science
• Biophysics

Background:

• X-ray scattering is crucial for understanding helical structures.
• Disorders in helical arrangements can significantly alter scattering patterns.
• Previous models have limitations in describing cumulative disorders.

Purpose of the Study:

• To investigate X-ray scattering from discrete helices with cumulative disorders.
• To analyze the applicability of the Barakat model for such systems.
• To elucidate the relationship between disorder and scattering intensity characteristics.

Main Methods:

• Utilized the Barakat model for X-ray scattering analysis.
• Assumed Gaussian distributions for angular and translational disorders between subunits.
• Equated the Barakat model to the paracrystalline model of the second kind.

Main Results:

• The Barakat model, under Gaussian disorder assumptions, is equivalent to the paracrystalline model of the second kind.
• Scattering intensity maxima decrease with increasing Bessel order.
• Peak breadth in the fiber direction and intensity minima increase with Bessel order.

Conclusions:

• The Barakat model effectively describes X-ray scattering from helices with cumulative disorders.
• Disorder significantly impacts the intensity distribution in X-ray scattering patterns.
• The findings provide insights into structural analysis of disordered helical materials.