| Abstract
| - Long-lived spin-correlated pairs were generated by laser irradiation of naphthalene (NAP) occludedas intact molecule within non-Brønsted acidic MnZSM-5 zeolites with MnSiO2)96-n(AlO2)n formula per unitcell. The laser UV photoionization generates primary NAP•+−electron pair as a fast phenomenon. Thesecharge carriers exhibit lifetimes that extend over less than 1 h at room temperature and disappear accordingto two parallel competitive ways: direct charge recombination and electron transfer. This subsequent electrontransfer takes place between the electron-deficient radical cation (NAP•+) and the electron-donor oxygenatom of zeolite framework. The aluminum rich MnZSM-5 zeolites (n = 3.4, 6.6) hinder efficiently the chargerecombination and promote the electron transfer to generate a very long electron−hole pair which exceedsseveral weeks at room temperature in NAP@Li6.6ZSM-5. The electron−hole pair exhibits broad visibleabsorption bands at 482 and 525 nm. The electron−hole distance, 1.3 nm, was deduced from the dipolarinteraction term (D) value. The spin density of trapped electron appears spread over 27Al, 29Si, 7Li, and 1Hnuclei as deduced by two-dimensional approach of hyperfine sublevel correlation (HYSCORE). The verylow recombination rate by tunneling effect was found to be in agreement with the very low value (J ≈ 0)of the magnetic exchange. The combined effects of tight fit between NAP size and straight-channeldimension, the high aluminum content of the framework, and the highly polarizing cation Li+ trapped efficientlythe ejected electron in the conduction band and the hole in the valence band of the porous materials.
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