Nitroprussides, a new group of materials for holographic information storage on the basis of metastable electronic states

Crystal structure of orthorhombic ferrous nitroprusside: Fe[Fe(CN)5NO].2H2O

“…In nitroprussides there is an empty low-energy antibonding orbital on the NO group which is accessible through light-induced charge transfer from the iron atom. This leads to the existence of long-living metastable electronic states which support potential applications of these complexes as holographic information storage materials (Haussühl et al , 1995; Imlau et al , 1999; Gutlich et al , 2001) and as optically switchable molecular communication devices (Gu et al , 1996; Gu et al , 1997). In addition, metal nitroprussides show properties as molecular sieves with a tunable system of channels, which allows the separation of molecules of small size (Boxhoorn et al , 1985; Balmaseda et al , 2003).…”

“…This leads to the existence of long-living metastable electronic states which support potential applications of these complexes as holographic information storage materials ͑Haussühl et al., 1995;Imlau et al, 1999;Gutlich et al, 2001͒ and as optically switchable molecular communication devices ͑Gu et al, 1996;Gu et al, 1997͒. In addition, metal nitroprussides show properties as molecular sieves with a tunable system of channels, which allows the separation of molecules of small size ͑Boxhoorn et al., 1985;Balmaseda et al, 2003͒. These and others potential applications of these complexes support the interest of their structural study.…”

Density functional study of nitroprusside: Mechanism of the photochemical formation and deactivation of the metastable states

“…In crystalline SNP at temperatures below 140 K, the metastable states have lifetimes greater than 10 4 s 24. Because of this property, this compound might be used as material for memory devices, in which information can be written by blue light and erased by red light, or energy storage and attracted therefore the interest of many researchers 25–27. Despite extensive studies, the nature of the two metastable states has been for a long time been the subject of debate.…”

Applications of photocrystallography: a future perspective

“…By focusing a laser onto the smallest area possible (a pixel) of a singlecrystal of this material in a particular direction, one selectively creates a photostructural change in a single dimension -defining a workable holographic data storage material. Indeed, electro-optic measurements and holographic light scattering experiments show that SNP belongs to a new class of photorefractive materials (Woike et al, 1994;Haussühl et al, 1995). This class is distinct from conventional photorefractive materials in its mechanistic origin (electric dipolar reversal due to this photoisomerism) and consequently, different associated kinetics (Fally et al, 2004).…”