Spin-exchange internal conversion (SEIC) is a general class of reactions having singlet fission, triplet fusion and triplet energy transfer as particular cases. Considering the charge transfer (CT) mediated mechanism and direct interaction mechanism, we propose proxies for estimating the coupling strength in both diabatic and adiabatic pictures for general SEIC reactions. In the diabatic picture, we took the linear relationship between charge-transfer (CT) coupling and frontier MO overlap and connected the coupling of Dexter energy transfer to the overlap of frontier molecular orbital (MO) with a quantitative correlation. With the quantum chemical calculation of triplet energy transfer in the noncovalent dimer of naphthalene and covalent dimer of fluorene, the proposed correlations are verified in detail. In the adiabatic picture, we showed that nonadiabatic couplings can be approximated by simple functions of the wave function CT coefficients. The approach was verified through the investigation of singlet oxygen photosensitization, where both 1Δg and 1Σg oxygen states can be competitively generated by a triplet fusion reaction.

Mechanism of spin-exchange internal conversion: Practical proxies for diabatic and nonadiabatic couplings

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.