Automatic fitting of multiple-field solid-state NMR spectra

Frédéric A Perras; Alexander L Paterson

doi:10.1016/j.ssnmr.2024.101935

Automatic fitting of multiple-field solid-state NMR spectra

Solid State Nucl Magn Reson. 2024 Jun:131:101935. doi: 10.1016/j.ssnmr.2024.101935. Epub 2024 Apr 7.

Authors

Frédéric A Perras¹, Alexander L Paterson²

Affiliations

¹ Chemical and Biological Sciences Division, Ames National Laboratory, Ames, IA, 50011, United States; Department of Chemistry, Iowa State University, Ames, IA, 50011, United States. Electronic address: fperras@ameslab.gov.
² National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, WI, 53706, United States.

PMID: 38603990
DOI: 10.1016/j.ssnmr.2024.101935

Abstract

The NMR lineshapes produced by half-integer quadrupolar nuclei are sensitive to 11 distinct fit parameters per inequivalent site. To date, automatic fitting routines have failed to replace manual parameter insertion and evaluation due to the importance of local minima and the need for fitting multiple-field magic-angle spinning (MAS) and static spectra simultaneously. Herein we introduce a new tool, AMES-Fit (Automatic Multiple Experiment Simulation and Fitting), to automatically find the global best-fit simulation parameters for a series of multiple-field NMR lineshapes. AMES-Fit uses an adaptive step size random search algorithm to dynamically probe parameter space and requires minimal human input. The best fits are obtained in a few minutes of computation time that would otherwise have required several person-hours of work. The program is freely available and open-source.

Keywords: Lineshape fitting; NMR software; Quadrupolar nuclei; Random search; Solid-state NMR.