Open AccessUltrafast X-ray Spectroscopy of Haem Proteins
Author(s) -
Camila Bacellar,
Majed Chergui
Publication year - 2022
Publication title -
chimia
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 0.387
H-Index - 55
eISSN - 2673-2424
pISSN - 0009-4293
DOI - 10.2533/chimia.2022.538
Subject(s) - spectroscopy , excited state , ultrafast laser spectroscopy , spin states , picosecond , photochemistry , x ray absorption spectroscopy , absorption spectroscopy , chemistry , porphyrin , ferric , myoglobin , dissociation (chemistry) , mössbauer spectroscopy , femtosecond , chromophore , ferrous , emission spectrum , crystallography , spectral line , atomic physics , inorganic chemistry , laser , physics , optics , organic chemistry , quantum mechanics , astronomy
In this article we revisit our recent picosecond and femtosecond X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) experiments, probing the ultrafast electronic and geometric evolution of photoexcited haem proteins, namely ferrous Nitrosyl Myoglobin (MbNO) and ferric Cytochrome c (Cyt c). We show through these two examples, combined with results from ultrafast optical spectroscopy, the universal behavior of the excited state dynamics of ferric and ferrous complexes. Regardless of the type of ligand, its dissociation or lack thereof, or the metal oxidation state, the photoexcited system relaxes through a cascade of excited spin states leading to formation of a high spin state, which in the case of the haem is a domed porphyrin.