Single-molecule spectroscopy of radical pairs, a theoretical treatment and experimental considerations

ABSTRACT

In this work, we propose to extend the scope of single-molecule spectroscopy to spin chemistry investigations of single radical pairs. A consistent theory of single-molecule spectroscopy on single radical pairs is proposed, which allows one to show that bunching phenomena are affected by singlet–triplet interconversion in radical pairs, which is, in turn, affected by local and external magnetic fields. A detailed study on the feasibility of such experiments with single flavin adenine dinucleotide, FAD, molecules is presented. We conclude that the observation of magnetic field effects on single FAD molecules is feasible but experimentally challenging for measurements on integrated fluorescence intensity and fluorescence event statistics.

GRAPHICAL ABSTRACT

KEYWORDS:

• Single molecule spectroscopy
• magnetic field effects
• flavin adenine dinucleotide
• radical pairs

Acknowledgements

E.A.N. and K.L.I. acknowledge the Russian Science Foundation (grant No. 15-13-20035) for financial support. N.I. and J.R.W acknowledge financial support for this work from JSPS KAKENHI (grant Number 17H03005). K.M. acknowledges financial support from JSPS KAKENHI (grant Number 18H01184) and the ‘Lab-to-Lab program’ in Saitama University for funding his travel to SCM 2017.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by JSPS KAKENHI [grant numbers 17H03005 and 18H01184]; Russian Science Foundation [grant number 15-13-20035].