Author
P. R. Fields
Bio: P. R. Fields is an academic researcher. The author has contributed to research in topics: Americium. The author has an hindex of 2, co-authored 3 publications receiving 642 citations.
Topics: Americium
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TL;DR: In this paper, the experimentally measured intensities of the solution absorption spectra of Pr3+, Nd3+, Er3+, Tm3+, and Yb3+ in three different solvents were correlated with a theoretical expression derived by Judd.
Abstract: We have correlated the experimentally measured intensities of the solution absorption spectra of Pr3+, Nd3+, Er3+, Tm3+, and Yb3+ in three different solvents with a theoretical expression derived by Judd. The expression, P=Σ lim λTλσ(fNψJ‖∪(λ)‖fNψJ′′)2λ=2,4,6 is derived from a theory in which the ligand‐field interactions with the central 3+ ion cause a mixing of higher configurations of opposite parity into the fN configuration and gives rise to induced electric‐dipole transitions. A prerequisite for the intensity calculations is the computation of complete intermediate coupling eigenvectors for the energy levels investigated. Other possible mechanisms such as magnetic‐dipole and electric‐quadrupole transitions are considered. The oscillator strengths of important magnetic‐dipole transitions are tabulated.The results give the first experimental verification of the ability of the theory to account for large changes in certain bands of the same lanthanide observed in different solvents. Conclusions are dra...
675 citations
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2,877 citations
TL;DR: In this article, the free-ion energy-level schemes of the Pr3+, Nd3+, Pm3+, Sm3+, Dy3, Dy3+, Ho3+, Er3+, and Tm3+ aquo ions have been determined from their absorption spectra in dilute acid solution at 25°.
Abstract: The free‐ion energy‐level schemes of the Pr3+, Nd3+, Pm3+, Sm3+, Dy3+, Ho3+, Er3+, and Tm3+ aquo ions have been determined from their absorption spectra in dilute acid solution at 25°. Energy‐level assignments were made by comparison with crystal spectra, and on the basis of correlations between calculated and observed band intensities. For most of the ions, it was possible to identify several transitions giving rise to bands at energies as high as 45 000–50 000 cm−1. Sufficient numbers of assignments were made to justify inclusion of the effects of configuration interaction in the calculation of the energy‐level parameters. Variation of the electrostatic, spin–orbit coupling, and configuration‐interaction parameters across the lanthanide series is examined.
2,689 citations
TL;DR: In this paper, the applicability of the well-known Judd-Ofelt theory to the emissive properties of Eu3+ complexes is investigated, and it is demonstrated experimentally that the radiative lifetime of the 5D0 excited state of the Eu 3+ can be calculated directly from its corrected emission spectrum, without using Judd-ofelt theory.
Abstract: Although luminescent complexes of lanthanide ions and organic ligands have been studied intensively, relatively little attention has been paid to the natural (or ‘radiative’) lifetime of the lanthanide centered luminescent state in these systems. Here, the applicability of the well-known Judd–Ofelt theory to the emissive properties of Eu3+ complexes is investigated. Moreover, it is demonstrated experimentally that the radiative lifetime of the 5D0 excited state of Eu3+ can be calculated directly from its corrected emission spectrum, without using Judd–Ofelt theory. We also discuss briefly the possibility of finding the natural lifetimes of lanthanide ions other than Eu3+.
1,142 citations
TL;DR: In this article, the experimentally determined band intensities in the solution absorption spectra of the trivalent lanthanides were correlated with a theoretical expression derived by Judd, and the spectra were measured in a single medium, dilute acid solution, and, in most cases, in the range ≈6000-50 000 cm−1.
Abstract: We have correlated the experimentally determined band intensities in the solution absorption spectra of the trivalent lanthanides with a theoretical expression derived by Judd. The spectra were measured in a single medium, dilute acid solution, and, in most cases, in the range ≈6000–50 000 cm−1. In general, the correlation between calculated and observed intensities was very good, even at higher energies. The variation of the intensity parameters over the series is discussed as is the somewhat unexpected degree of correlation obtained in the ultraviolet region.
1,019 citations
TL;DR: This review provides an overview of the latest advances in Ln(3+)-containing siloxane-based hybrids, with emphasis on the different possible synthetic strategies, photoluminescence features, empirical determination.
Abstract: Interest in lanthanide-containing organic-inorganic hybrids has grown considerably during the last decade, with the concomitant fabrication of materials with tunable attributes offering modulated properties. The potential of these materials relies on exploiting the synergy between the intrinsic characteristics of sol-gel derived hosts (highly controlled purity, versatile shaping and patterning, excellent optical quality, easy control of the refractive index, photosensitivity, encapsulation of large amounts of isolated emitting centers protected by the host) and the luminescence features of trivalent lanthanide ions (high luminescence quantum yield, narrow bandwidth, long-lived emission, large Stokes shifts, ligand-dependent luminescence sensitization). Promising applications may be envisaged, such as light-emitting devices, active waveguides in the visible and near-IR spectral regions, active coatings, and bio-medical actuators and sensors, opening up exciting directions in materials science and related technologies with significant implications in the integration, miniaturization, and multifunctionalization of devices. This review provides an overview of the latest advances in Ln(3+)-containing siloxane-based hybrids, with emphasis on the different possible synthetic strategies, photoluminescence features, empirical determination.
849 citations