1. Could you explain the significance of your article to the non-specialist? 

Electron Paramagnetic Resonance (EPR) is capable of 'sensing' the chemical environment surrounding free radicals probe molecules. In the last years there has been a surge of applications of EPR methods for characterizing molecular systems in life sciences, materials sciences, and applied chemistry. But in order to properly analyze an EPR spectrum one needs refined theoretical tools, from the world of quantum mechanics calculations and from the world of statistical thermodynamics. It is quite a challenge, for a theoretical chemist, to combine them in an integrated working approach and we have tried in this work to show a possible route to accomplish this task. 

2. What has motivated you to conduct this work? 

There are two main motivations behind our work. The first one is that we believe that EPR has the potentiality of becoming one of the most powerful experimental methods of investigation on the electron distribution in molecules, and on the properties of their environments. The need of fast, effective and non-biased interpretative computational techniques is evident. The second stimulus comes from the desire to bridge the gap between advanced quantum chemical and statistical thermodynamics approaches, which is the only way, in our opinion, to address properly interpretation of spectroscopic data. 

3. Where do you see this work developing in the future? 

A likely development is the realization of user-friendly 'black-box' software able to predict, from the structure of the molecular probe and diverse information on the chemical environment, the full EPR spectrum. We believe that such a tool would be very valuable in many contexts, like, for instance, analysis of site direct spin labelling (SDSL) experiments in proteins. In general, a truly integrated computational approach can be relevant for other spectroscopies, and we are currently working intensely on nuclear magnetic resonance (NMR) and non-linear optical spectroscopies. 

4. Are there any particular challenges facing future research in this area? 

A fundamental development goes in the direction of uplifting current theoretical approaches to include slow relaxing probe and solvent dynamics in the core of quantum mechanical electronic calculations. The real challenge in the field of theoretical and computational chemistry applied to interpretation of complex spectroscopic observables - of which EPR is one of the most relevant but not unique examples - lies in establishing a common language between quantum chemists and statistical thermodynamics chemists.