Cross-correlation analysis of X-ray photon correlation spectroscopy to extract rotational diffusion coefficients

Area of Science:

• Physics
• Materials Science
• Physical Chemistry

Background:

• Brownian motion is fundamental to particle dynamics, characterized by translational and rotational diffusion coefficients.
• X-ray photon correlation spectroscopy (XPCS) is a powerful technique for studying Brownian motion across various length and time scales.
• Current XPCS analysis methods effectively determine translational diffusion but lack algorithms for rotational diffusion coefficients.

Purpose of the Study:

• To develop a novel method for calculating rotational diffusion coefficients using XPCS data.
• To introduce a numerical algorithm, Multi-Tiered Estimation for Correlation Spectroscopy (MTECS), for this purpose.
• To demonstrate the applicability of the proposed method beyond its initial experimental regime.

Main Methods:

• Angular-temporal cross-correlation analysis of XPCS data.
• Development of the Multi-Tiered Estimation for Correlation Spectroscopy (MTECS) numerical algorithm.
• Validation of the MTECS algorithm using simulated XPCS data across various conditions.

Main Results:

• Successful extraction of rotational diffusion information from XPCS data.
• Demonstration that angular-temporal cross-correlation analysis enables rotational diffusion coefficient prediction.
• Verification of the MTECS algorithm's accuracy through simulations.

Conclusions:

• The proposed angular-temporal cross-correlation analysis provides a viable pathway to measure rotational diffusion coefficients using XPCS.
• The MTECS algorithm offers a practical solution for obtaining rotational diffusion data from existing XPCS experiments.
• This advancement expands the utility of XPCS for comprehensive particle dynamics characterization.