Showing papers by "Andreas Hauser published in 2002"
TL;DR: In this article, it was shown that the quantum efficiency of the photoconversion at 11 K is on the order of unity, with no noticeable dependence on irradiation intensity, however, it does depend to some extent on the fraction of complexes already converted to the high-spin state.
Abstract: [Fe(pic)3]Cl2·EtOH (pic = 2-picolylamine) is a spin-crossover compound that can be converted from the low-spin state to the high-spin state at temperatures below the thermal transition temperature by way of light irradiation in the visible part of the electromagnetic spectrum. For this compound, the question regarding the quantum efficiency of this photoconversion process and its possible dependence on irradiation intensity gave rise to some controversy. The experimental results presented in this paper demonstrate that the quantum efficiency of the photoconversion at 11 K is on the order of unity, with no noticeable dependence on irradiation intensity. It does, however, depend to some extent on the fraction of complexes already converted to the high-spin state.
52 citations
TL;DR: In this paper, a ruthenium complex with a 6,7-dicyanosubstituted dppz ligand has been synthesized, and its crystal structure and physico-chemical studies are reported.
Abstract: A novel ruthenium complex with a 6,7-dicyanosubstituted dppz ligand has been synthesised: its crystal structure and physico-chemical studies are reported.
27 citations
TL;DR: In this paper, the authors show that the R1 line of the 4A2 → 2E transition of the [Cr(ox)3]3- chromophore in mixed crystal [Rh(bpy)3][NaAl1-xCrx(ox),3]ClO4 (x = 0.05−0.9, ox = oxalate, bpy = 2,2'-bipyridine).
Abstract: Efficient resonant energy transfer occurs within the R1 line of the 4A2 → 2E transition of the [Cr(ox)3]3- chromophore in mixed crystal [Rh(bpy)3][NaAl1-xCrx(ox)3]ClO4 (x = 0.05−0.9, ox = oxalate, bpy = 2,2'-bipyridine). This manifests itself in the form of multiline patterns in resonant fluorescence line narrowing (FLN) experiments at 1.5 K. The conditions for such a resonant process to occur are that the inhomogeneous line width of the R1 line is larger than the zero-field splitting of the ground state, which, in turn, is larger than the homogeneous line width of the transition. The number of lines and their relative intensities depend critically upon the [Cr(ox)3]3- concentration and the excitation wavelength within the inhomogeneous distribution. The basic model for resonant energy transfer as presented by von Arx et al. (Phys. Rev B 1996, 54, 15800) is extended to include the effects of diluting the chromophores in an inert host lattice and of nonresonant R2 excitation. In addition, Monte Carlo simulations serve to explain the temporal evolution of the multiline pattern following pulsed excitation.
13 citations
TL;DR: In this article, the authors showed that the [Ru(bpy)3][LiCr(ox)3] system has two crystallographically non-equivalent sites, and that resonant and non-resonant fluorescence line narrowing (FLN) experiments on the R1 lines of these sites were conducted at 1.6 K.
Abstract: The [Ru(bpy)3][LiCr(ox)3] system (bpy = 2,2'-bipyridine, ox = oxalate) has two crystallographically non-equivalent [Cr(ox)3]3- sites. In steady-state resonant and nonresonant fluorescence line narrowing (FLN) experiments on the R1 lines of the two non-equivalent [Cr(ox)3]3- chromophores, multiline spectra are observed at 1.6 K. Such multiline spectra are clear evidence for resonant energy transfer processes within the inhomogeneously broadened R1 lines. In addition, time-resolved experiments show that also site-to-site energy transfer occurs, which turns out to be resonant, too, however with a non-negligible phonon-assisted contribution even at 1.5 K.
4 citations