Karl A. Gschneidner, Jr., Jean-Claude G. Bünzli, Vitalij K. Pecharsky

These elements perplex us in our rearches [sic], baffle us in our speculations, and haunt us in our very dreams. They stretch like an unknown sea before us – mocking, mystifying, and murmuring strange revelations and possibilities.

Sir William Crookes (February 16, 1887)

Chapter 231. First-principles calculations of transition spectra by Kazuyoshi Ogasawara, Shinta Watanabe, Hiroaki Toyoshima and Mikhail G. Brik Kwansei Gakuin University, 2-1 Gakuen, Sanda, Japan

Due to the growing demand for lasers and phosphors operating in UV and VUV regions, a great deal of attention is being paid now to the thorough analysis of high-lying energy levels of lanthanide (R) ions arising from their 4fn and 4fn−15d1 electronic configurations. This chapter reviews the recent development of the first-principles analysis of the spectra of R ions in crystals. It starts with a brief review of the commonly used semi-empirical crystal-field calculations and with a historical overview of the first-principles calculations for multiplet states of metal ions in crystals. A detailed description of the relativistic discrete variational multielectron (DVME) method follows, a first-principles relativistic many-electron calculation method developed by the authors. The major part of the chapter is then devoted to the recent achievements on DVME calculations and analyses of the energy level schemes and spectra of R ions in a free state and in crystals. The Dieke diagram is theoretically extended and the origins of peaks in the spectra are clarified based on the explicit many-electron wavefunctions. An application to the analysis of a commercially-used blue phosphor, BaMgAl10O17:Eu2+ (BAM:Eu2+), is also given.

Chapter 232. transitions by Gary W. Burdick and Mike F. Reid Andrews University, Berrien Springs, MI, USA and University of Canturbury, Christchurch, New Zealand

Numerous applications of lanthanide materials, including scintillators, visible ultraviolet (VUV) lasers, and phosphors for fluorescent lighting and plasma displays, make use of the excited configuration. Obviously, understanding of these states is crucial to the development of advanced materials. This chapter reviews an extension of the parametric model originally developed by Carnall, Wybourne and Dieke to treat spectra. The authors of this chapter show that the extended model may and has been successfully employed to calculate the absorption and emission spectra for the configuration. The review illustrates how parametrization can be applied to calculate other properties of interest, such as non-radiative relaxation rates, thus explaining the major features of the UV and VUV spectra for ions across the entire lanthanide series. The chapter concludes with a discussion of the relationship between parametrized calculations and other approaches, such as ab initio calculations.

Chapter 233. Spectroscopic properties of lanthanides in nanomaterials by Guokui Liu and Xueyuan Chen Argonne National Laboratory, USA and Fujian Institute of Research on the Structure of Matter, Fuzhou, China

This chapter reviews recent studies on energy levels and excited state dynamics of lanthanides (R) in nano-structures, which include R-doped dielectric nano-crystals, implanted nano-particles of semiconductors, coated core–shell nano-particles, nano-tubes and nano-balls stuffed with R ions. New phenomena such as the action of confinement on ion–phonon interaction and its consequences for electronic transitions, energy transfer, and phase transitions are discussed in the light of experimental and theoretical studies reported in the literature. Although the review aims at being comprehensive and covers all the important aspects in the field, emphasis is given to identification and theoretical analysis of various mechanisms for luminescence enhancement, or quenching, and anomalous size- and temperature-dependence of photophysical properties.

Chapter 234. Lanthanide chelates as luminescent labels in biomedical analyses by Takuya Nishioka, Kôichi Fukui, and Kazuko Matsumoto Waseda University and Japan Science and Technology Agency, Tokyo, Japan

Recent advances in time-resolved spectroscopy (TRS) using luminescent lanthanide labels for biomedical analyses are reviewed. The large Stokes shift and long-lived excited states specific to some lanthanide chelates allow the use of TRS for these analyses, which effectively removes background fluorescence of the samples. This enables the measurement of very small signals which could not be detected in conventional fluorometric analyses based on organic dye labels. The resulting high signal-to-noise ratios leads to the determination of trace amounts of targeted proteins, nucleic acids or any other biomolecules with unusually high sensitivity. The chapter includes a description of the synthesis of luminescent lanthanide chelates and of their physical properties. The advantage of luminescence resonance energy transfer (LRET) and luminescence quenching are explained in relationship to the specific properties of the lanthanide chelates used as luminescent labels. Medical applications of lanthanide chelates in immunoassays, DNA hybridization assays, receptor-ligand binding assays, and imaging are reviewed.

Chapter 235. Lanthanide near-infrared luminescence in molecular probes and devices by Steve Comby and Jean-Claude G. Bünzli École Polytechnique Fédérale de Lausanne (EPFL), Switzerland

Interest for lanthanide-containing near-infrared (NIR) emitting compounds stemmed initially from the development of lasers, optical fibers and amplifiers for telecommunications. Up-conversion processes have also been the subject of much attention. More recently, it was realized that biological tissues are transparent to light in the range 700–1000 nm, allowing optical detection of tumors. This review concentrates mainly on discrete molecular edifices containing NdIII, ErIII, or YbIII, although systems containing other NIR-emitting RIII ions are also mentioned. It starts with a general description of the photophysical properties of NIR-emitting lanthanide ions and of their sensitization before systematically reviewing the various classes of compounds used for designing NIR-emitting lanthanide probes. Macrocyclic ligands are described first (porphyrins, coronands, cryptands, cyclen derivatives, calixarenes), followed by acyclic ligands, among them beta-diketonates are a privileged and much studied group of chelates. New strategies are described, which make use of podands, dendrimers, or self-assembly processes, as well as of sensitization through d-transition metal ions. The overview ends by the description of NIR-emitting ions embedded into extended structures, coordination polymers, inorganic clusters, zeolites, microporous materials, microspheres and nanoparticles. The last part of the chapter focuses on potential applications, including liquid lasers, optical fibers and amplifiers, light-emitting diodes, and analytical applications, including biomedical analyses. As an aid to future work in the field, comprehensive tables compare the effectiveness of the...