Chemistry
A general signal expression with power-law decay for spin self-diffusion in a nonlinear gradient field
Document Type
Article
Abstract
Signal attenuation in diffusion NMR and MRI is commonly described using Gaussian phase statistics, which fail under nonlinear gradient fields. Using the effective phase diffusion method (EPDM) and the short-gradient-pulse approximation, we show that signal attenuation arising from Brownian self-diffusion of spins near the origin of a nonlinear gradient field follows a power-law decay rather than conventional exponential attenuation. We propose a compact signal expression that agrees with numerical and simulation results over a broad attenuation range. Within the EPDM framework, the diffusion phase variance naturally incorporates finite gradient-pulse-width effects, enabling extension to general gradient waveforms. Copyright © 2026. Published by Elsevier B.V.
Publication Title
Chemical Physics Letters
Publication Date
10-2026
Volume
897
ISSN
0009-2614
DOI
10.1016/j.cplett.2026.142969
Keywords
non-Gaussian phase, nonlinear gradient field, power-law decay, spin diffusion
Repository Citation
Lin, Guoxing and Xu, Chenghao, "A general signal expression with power-law decay for spin self-diffusion in a nonlinear gradient field" (2026). Chemistry. 234.
https://commons.clarku.edu/chemistry/234
