Probing the electronic structure of imidazole complexes in solution with quantum chemistry and X-ray absorption spectroscopy

• By combing soft X-ray spectroscopy and theoretical calculations, characterization of the shared proton in the imidazole molecular complex has been done. With nitrogen core-level excitations as a sensitive reporter about the protonation status, a new absorption resonance is observed at a pH where exactly half of the imidazoles are protonated, right between the known absorptions of pure imidazole and pure imidazolium. Supported by TDDFT calculations, the spectral signature has been assigned to the sharing of the excess proton between two imidazole molecules in an asymmetric double minimum potential. Analysis of the discrete core excitations reveals shared electronic attributes between the molecular complex and individual monomers. The theoretical investigation also uncovers the influence of the shared proton on the intrinsic features and the overall spectral outcome.

Ämnesord

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

NATURVETENSKAP  -- Kemi -- Teoretisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Theoretical Chemistry (hsv//eng)

Nyckelord

X-ray absorption spectroscopy

TDDFT

N K-edge spectra

Shared proton

kemisk fysik

Chemical Physics

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vet (ämneskategori)

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