Photoinduced ferrimagnetic systems in Prussian blue analogues C-x(I)Co-4[Fe(CN)(6)](y) (C-I = alkali cation). 2. X-ray absorption spectroscopy of themetastable state

CoFe Prussian blue analogue Rb1.8Co4[Fe(CN)(6)](3.3). 13H(2)O was synthesiz ed, which presents an important photomagnetic effect. The electronic struct ure and the local structure of the ground and of the excited states have be en investigated. X-ray absorption spectroscopy measurements at the Co and F e L-2.3 edges and cobalt K-edge (XANES and EXAFS) evidence the local electr onic transfer and the spin change of the cobalt ions induced by irradiation . We observed a 0.19 Angstrom increase of the Co-N bond length, associated with the transformation of Co-III low spin to Co-II high spin. The Co-II/Co -III ratio has been evaluated as a function of the irradiation time and rev ealed as an important parameter to understanding the bulk magnetic properti es. The combined role of the diamagnetic Fe-II-Co-III pairs and hexacyanofe rrate(III) vacancies is locally evidenced. This work is a new step in the u nderstanding of the photoinduced electron transfer.