TY - JOUR
T1 - Photoinduced dynamics in an exchange-coupled trinuclear iron cluster
AU - Liedy, Florian
AU - Shi, Rui
AU - Coletta, Marco
AU - Vallejo Navarret, Julia
AU - Brechin, Euan
AU - Lefkidis, Georgios
AU - Huebner, Wolfgang
AU - Johansson, Johan Olof
PY - 2020/5/1
Y1 - 2020/5/1
N2 - We present a joint experimental and computational study of the trinuclear basic carboxylate iron complex Fe Fe O(CH CO ) (H O) III2 II 3 26 2 3, which is a model system for understanding photoinduced ultrafast spin dynamics in magnetic iron-based transition metal oxides. We have carried out femtosecond optical transient absorption spectroscopy of molecules in solution at room-temperature exciting either at 400 or 520 nm and observed a longlived excited-state absorption (ESA) signal from ca. 400–670 nm. The ESA signal is composed of several broadun-resolved bands at 405, 440 and 530 nm. The decay dynamics are complicated and three exponentials with corresponding decay time constants of τ1 = ± 360 30 fs, τ2 = ± 5.3 0.6 ps, τ3 = ± 65 5 ps and a constant offset (τ4 > 500 ps) were needed to fit the data over the full wavelength range. The data indicate that the lowest excited state is populated within the duration of the excitation pulse (<120 fs). Highly correlated coupled-cluster calculations can satisfactorily reproduce the experimental vibrational spectrum and highlight the role of the μ3-oxo bridge connecting the Fe ions to create a highly correlated ground-state and identify the excited state as having a mixture of both charge-transfer and ligand-field/d-orbital characters.
AB - We present a joint experimental and computational study of the trinuclear basic carboxylate iron complex Fe Fe O(CH CO ) (H O) III2 II 3 26 2 3, which is a model system for understanding photoinduced ultrafast spin dynamics in magnetic iron-based transition metal oxides. We have carried out femtosecond optical transient absorption spectroscopy of molecules in solution at room-temperature exciting either at 400 or 520 nm and observed a longlived excited-state absorption (ESA) signal from ca. 400–670 nm. The ESA signal is composed of several broadun-resolved bands at 405, 440 and 530 nm. The decay dynamics are complicated and three exponentials with corresponding decay time constants of τ1 = ± 360 30 fs, τ2 = ± 5.3 0.6 ps, τ3 = ± 65 5 ps and a constant offset (τ4 > 500 ps) were needed to fit the data over the full wavelength range. The data indicate that the lowest excited state is populated within the duration of the excitation pulse (<120 fs). Highly correlated coupled-cluster calculations can satisfactorily reproduce the experimental vibrational spectrum and highlight the role of the μ3-oxo bridge connecting the Fe ions to create a highly correlated ground-state and identify the excited state as having a mixture of both charge-transfer and ligand-field/d-orbital characters.
U2 - 10.1016/j.jmmm.2020.166476
DO - 10.1016/j.jmmm.2020.166476
M3 - Article
SN - 0304-8853
VL - 501
JO - Journal of Magnetism and Magnetic Materials
JF - Journal of Magnetism and Magnetic Materials
ER -