High Pressure Probes of Electronic Structure and Luminescence Properties of Transition Metal and Lanthanide Systems

PRESSURE-INDUCED CHANGE OFd-dLUMINESCENCE ENERGIES, VIBRONIC STRUCTURE AND BAND INTENSITIES IN TRANSITION METAL COMPLEXES

“…Luminescence and absorption spectra of many transition metal compounds, including organometallic molecules, have been measured and pressure-induced variations have been reported for the energies of their band maxima. [1,3,4,6,7] Excited states with different multiplicities are often close in energy, as illustrated by numerous studies of octahedral chromium(III) complexes, where an emitting state crossover from a quartet to a doublet state has been observed. [6] The corresponding change from a triplet to a singlet emitting state for an octahedral vanadium(III) complex was recently reported.…”

“…[1,3,4,6,7] Excited states with different multiplicities are often close in energy, as illustrated by numerous studies of octahedral chromium(III) complexes, where an emitting state crossover from a quartet to a doublet state has been observed. [6] The corresponding change from a triplet to a singlet emitting state for an octahedral vanadium(III) complex was recently reported. [8] Many literature studies focus on pressure-induced spectroscopic effects caused by ground-state metal-ligand bond length changes, illustrated for example by spin-crossover complexes, where pressure can lead to very large metal-ligand bond length changes and even to crystallographic phase transitions.…”

“…[1][2][3][4][5][6][7] Transition metal complexes are particularly attractive for the study of pressure effects, due to their high symmetry and electronic structure with degenerate and nondegenerate electronic states. Luminescence and absorption spectra of many transition metal compounds, including organometallic molecules, have been measured and pressure-induced variations have been reported for the energies of their band maxima.…”

Effect of External Pressure on the Excitation Energy Transfer from [Cr(ox)3]3− to [Cr(bpy)3]3+ in [Rh1−xCrx(bpy)3][NaM1−yCry(ox)3]ClO4

“…For spin-flip transitions, that is, transitions within the same electronic configuration, the nephelauxetic effect dominates and thus these generally shift to lower energies. [7] In the present paper we report the shift rates for the spinflip transitions of [Cr(ox) 3 ] 3À and [Cr(bpy) 3 ] 3 + in high pressure experiments. As the two shift rates differ considerably, the spectral overlap between the respective donor and acceptor transitions becomes a function of external pressure, and therefore external pressure directly influences the quantum efficiency of the resonant energy transfer.…”

Pressure-induced changes inCr3+-doped elpasolites andLiCaAlF6: Interpretation of macroscopic data

“…[1][2][3] In this domain of research, particular attention has been paid to the changes in optical properties induced by an applied pressure. 4 Indeed pressure modifies the energy of electronic transitions related to a transition-metal complex, a property widely used for measuring the actual value of pressure in diamond-anvil cells using the Cr 3+ emission. 5,6 Moreover, in the case of halide host lattices doped with Cr 3+ ions pressure can change the nature of the first excited state responsible for the luminescence.…”