Light-induced structural changes by excitation of metastable states in Na2[Fe(CN)5NO]2H2O single crystals

Abstract

The structures of the ground state and the light-induced metastable state SI of ${\mathrm{Na}}_2\left[\mathrm{Fe}\right(\mathrm{CN}{)}_5\mathrm{NO}]2{\mathrm{H}}_2\mathrm{O}$ were investigated by single-crystal neutron diffraction. We propose that a small but significant change in the Fe-N bond length $\left(\approx 0.05\mathrm{\AA }\right)$ and in the C-Fe-N angle $\left(\approx 3.5°\right)$ are the only rearrangements in the structure connected with the excitation of the metastable state SI. This result is consistently found for two data sets with different populations $(22\%$ and $44\%)$ of the metastable state SI.