Time-resolved investigation of photoinduced structural change in Co-Fe cyanides

Photoexcited effects have been investigated for Co-Fe cyanides, K 0 . 1 8 Co[Fe(CN) 6 ] 0 . 8 2 .4.57H 2 O and K 0 . 4 5 Co[Fe(CN) 6 ] 0 . 8 7 .4.80H 2 O, by means of the transient absorption method. For both the compounds, the photoexcitation at 532 nm induces a structural change into a metastable phase at 91 K, and the relaxation time τ exponentially decreases as temperature increases. We have found a faster decay process (τ 2 = 10-40 ms) that dominates above ∼220 K, and discuss its interrelation with the photoinduced structural change.