Implementing a new EPR lineshape parameter for organic radicals in carbonaceous matter

Mathilde Bourbin,Laurent Binet,Yann Le Du,Didier Gourier

doi:10.1186/1751-0473-8-15

Abstract

BackgroundElectron Paramagnetic Resonance (EPR) is a non-destructive, non-invasive technique useful for the characterization of organic moieties in primitive carbonaceous matter related to the origin of life. The classical EPR parameters are the peak-to-peak amplitude, the linewidth and the g factor; however, such parameters turn out not to suffice to fully determine a single EPR line.ResultsIn this paper, we give the definition and practical implementation of a new EPR parameter based on the signal shape that we call the R10 factor. This parameter was originally defined in the case of a single symmetric EPR line and used as a new datation method for organic matter in the field of exobiology.ConclusionCombined to classical EPR parameters, the proposed shape parameter provides a full description of an EPR spectrum and opens the way to novel applications like datation. Such a parameter is a powerful tool for future EPR studies, not only of carbonaceous matter, but also of any substance which spectrum exhibits a single symmetric line.ReproducibilityThe paper is a literate program—written using Noweb within the Org-mode as provided by the Emacs editor— and it also describes the full data analysis pipeline that computes the R10 on a real EPR spectrum.

Highlights

Electron Paramagnetic Resonance (EPR) is a non-destructive, non-invasive technique useful for the characterization of organic moieties in primitive carbonaceous matter related to the origin of life
A novel solution based on Electron Paramagnetic Resonance (EPR) was proposed [1]; it requires the determination of a new EPR parameter, the R10, from the EPR spectrum of the rock sample, from which the age can be computed from an empirical log-linear correlation that was uncovered in [1]
Electron Paramagnetic Resonance (EPR) is a nondestructive and non-invasive technique which has long been used for the study of paramagnetic defects in carbonaceous materials

Summary

Introduction

Electron Paramagnetic Resonance (EPR) is a non-destructive, non-invasive technique useful for the characterization of organic moieties in primitive carbonaceous matter related to the origin of life. A novel solution based on Electron Paramagnetic Resonance (EPR) was proposed [1]; it requires the determination of a new EPR parameter, the R10, from the EPR spectrum of the rock sample, from which the age can be computed from an empirical log-linear correlation that was uncovered in [1]. Electron Paramagnetic Resonance (EPR) is a nondestructive and non-invasive technique which has long been used for the study of paramagnetic defects (organic radicals) in carbonaceous materials. Such defects have been detected with high sensitivity in coals by pioneering EPR works [3]. For a single set of those three parameters, various lineshapes are possible (Figure 1); to fully determine the EPR line, a new EPR parameter, based on the lineshape, had to be defined

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