title: The photo-induced commensurate modulated structure in site-selective spin crossover complex trans-[Fe(abpt)(2)(NCS)(2)].
abstract: The photo-induced superstructure of polymorph C of trans-[Fe(abpt)(2)(NCS)(2)] (abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) is discovered as a commensurate modulated structure by single-crystal X-ray diffraction under irradiation. The crystal structure at 25 K before the photo-irradiation composed of two crystallographically independent iron molecules, one of which exhibits high spin (HS) state and the other at low spin (LS) state. Under green laser light (λ = 532 nm) irradiation, the LS molecule (Fe1) is found to be excited to a metastable HS state and gives rise to a commensurate tripled superstructure along the c axis. In addition, it is confirmed that this modulation persists until the HS → LS relaxation temperature beyond 52 K. Our structural findings suggest that the structural modulation and the site-selective LS → HS excitation are highly correlated.
authors.affiliation: Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba, 277-561, Japan.
authors.forename: Che-Hsiu
authors.initials: CH
authors.lastname: Shih
authors.forename: Chou-Fu
authors.initials: CF
authors.lastname: Sheu
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kato
authors.forename: Kunihisa
authors.initials: K
authors.lastname: Sugimoto
authors.forename: Jungeun
authors.initials: J
authors.lastname: Kim
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Masaki
authors.initials: M
authors.lastname: Takata