2024/08/04 by Alberto Privitera, Alessandro Chiesa, Privitera, Alberto +19 · 1 citation
Chemistry · Materials Science · #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Magnetism in coordination complexes #Photochemistry and Electron Transfer Studies #Porphyrin and Phthalocyanine Chemistry #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2408.02104
openalex publication_date 2024/08/04 · openalex created_date 2025/01/17 · openalex updated_date 2026/07/28
Photoexcited organic chromophores appended to molecular qubits can serve as a source of spin initialization or multi-level qudit generation for quantum information applications. So far, this approach has been primarily investigated in chromophore/stable radical systems. Here, we extend this concept to a meso-meso linked oxovanadium(IV) porphyrin - free base porphyrin dimer. Femtosecond transient absorption experiments reveal that photoexcitation of the free base porphyrin leads to picosecond triplet state formation via enhanced intersystem crossing. Time-resolved electron paramagnetic resonance (TREPR) experiments carried out at both 85 K and room temperature reveal the formation of a long-lived spin-polarized quartet state through triplet-doublet spin mixing. Notably, a distinct hyperfine structure arising from the interaction between the electron spin quartet state and the vanadyl nucleus (51V, I=7/2) is evident, with the quartet state exhibiting long-lived spin polarization even at room temperature. Theoretical simulations of the TREPR spectra confirm the photogenerated quartet state and provide insights into the non-Boltzmann spin populations. Exploit-ing this phenomenon affords the possibility of using photoinduced triplet states in porphyrins for quantum information as a resource to polarize and magnetically couple molecular electronic or nuclear spin qubits and qudits.