Optical methods for the evaluation of the thermal ionization barrier of lanthanide excited states in luminescent materials

The theory of thermal ionization of gases was first given by M. N. Saha in a series of papers (1920 a , 1920 b , 1921) and widely applied by him and others to furnish a satisfactory physical theory of stellar spectra. The theory was further developed by Fowler (1923) to include the different excited states of the atom and of the ionized atom, all of which are simultaneously in thermodynamical equilibrium. At the time when the theory was first formulated the ionization potentials and the spectral characteristics of only a few elements were known, but now we possess almost a complete knowledge of the ionization potentials and the spectra of almost all the elements in their different stages of ionization. Hence a detailed comparison of the theory with experimental results can now be satisfactorily undertaken.

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Insights into the complexity of the excited states of Eu-doped luminescent materials

Inorganic Chemistry Frontiers ◽

10.1039/c9qi01455a ◽

2020 ◽

Vol 7 (4) ◽

pp. 871-888 ◽

Cited By ~ 4

Author(s):

Jonas J. Joos ◽

Philippe F. Smet ◽

Luis Seijo ◽

Zoila Barandiarán

Keyword(s):

Chemical Composition ◽

Ab Initio ◽

Excited States ◽

Luminescent Materials ◽

Cluster Methods

Multiconfigurational ab initio embedded-cluster methods give a detailed view of the excited states of Eu-doped luminescent materials, improving the understanding of their structure and how it is affected by changing the host's chemical composition.

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Narcissistic Self-Sorting and Enhanced Luminescence via Catenation in Water

10.21203/rs.3.rs-825032/v1 ◽

2021 ◽

Author(s):

Qiong Chen ◽

Ye Lei ◽

Hongye Wang ◽

Guangcheng Wu ◽

Wenwen Xu ◽

...

Keyword(s):

Conceptual Model ◽

Excited States ◽

Self Assembly ◽

Luminescent Materials ◽

Enhanced Fluorescence ◽

Enhanced Luminescence ◽

Intramolecular Motions

Abstract Narcissistic self-sorting, namely that components are able to distinguish “self” from “nonself” during self-assembly, was accomplished via catenation by condensing multiple hydrazides and an aldehyde, or a hydrazide and multiple aldehydes in water. The underneath mechanism of this behavior relies on the corresponding homo [2]catenanes are thermodynamically more favored than their hetero counterparts, because the former containing two identical macrocyclic components are able to maximize the inter-component noncovalent forces. One of these catenanes contains four 4-phenylpyridinium units, which are often considered barely luminescent due to intramolecular rotations and vibrations that lead to nonradiative annihilation of their excited states. These intramolecular motions, however, are restricted upon integrating 4-phenylpyridiniums within the catenane architecture. As a consequence, compared to its non-interlocked counterparts, this catenane exhibits enhanced fluorescence, which represents a novel conceptual model for developing luminescent materials.

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Layered double hydroxides-based smart luminescent materials and the tuning of their excited states

Cell Reports Physical Science ◽

10.1016/j.xcrp.2021.100536 ◽

2021 ◽

Vol 2 (8) ◽

pp. 100536

Author(s):

Rui Gao ◽

Dongpeng Yan ◽

Xue Duan

Keyword(s):

Excited States ◽

Layered Double Hydroxides ◽

Luminescent Materials ◽

Double Hydroxides

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Vuv Spectra Y to Mo

International Astronomical Union Colloquium ◽

10.1017/s0252921100107808 ◽

1988 ◽

Vol 102 ◽

pp. 239

Author(s):

M.S.Z. Chaghtai

Keyword(s):

Excited States ◽

Spectral Analyses ◽

Vuv Spectra

Using R.D. Cowan’s computations (1979) and parametric calculations of Meinders et al (1982), old analyses are thoroughly revised and extended at Aligarh, of Zr III by Khan et al (1981), of Nb IV by Shujauddin et Chaghtai (1985), of Mo V by Tauheed at al (1985). Cabeza et al (1986) confirmed the last one largely.Extensive studies have been reported of the 1–e spectra, Zr IV (Rahimullah et al 1980; Acquista and Reader 1980), Nb V (Shujauddin et al 1982; Kagan et al 1981) and Mo VI (Edlén et al 1985). Some interacting 4p54d2levels of these spectra have been reported from our laboratory, also.Detailed spectral analyses of transitions between excited states have furnished complete energy values for J ≠ 1 levels of these spectra during 1970s and 80s. Shujauddin et al (1982) have worked out Nb VI and Tauheed et al (1984) Mo VII from our lab, while Khan et al (1981) share the work on Zr V with Reader and Acquista (1979).

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Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010679x ◽

1988 ◽

Vol 46 ◽

pp. 946-947

Author(s):

A. Legrouri

Keyword(s):

Aqueous Solution ◽

Thermal Decomposition ◽

Physicochemical Properties ◽

Surface Area ◽

Vanadium Pentoxide ◽

High Purity ◽

Gas Adsorption ◽

Rhodium Catalyst ◽

Optical Methods ◽

Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

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Investigation of cluster layers of small netal particles by TEM, SEM, EELS and by photoacoustic spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100174382 ◽

1990 ◽

Vol 48 (4) ◽

pp. 250-251

Author(s):

H. Seiler ◽

U. Haas ◽

K.H. Körtje

Keyword(s):

Bulk Material ◽

High Vacuum ◽

Optical Methods ◽

Metal Particles ◽

Silver Particles ◽

Low Loss ◽

Plasmon Excitation ◽

First Results ◽

Diffraction Patterns ◽

Small Metal Particles

The physical properties of small metal particles reveal an intermediate position between atomic and bulk material. Especially Ag has shown pronounced size effects. We compared silver layers evaporated in high vacuum with cluster layers of small silver particles, evaporated in N2 at a pressure of about 102 Pa. The investigations were performed by electron optical methods (TEM, SEM, EELS) and by Photoacoustic (PA) Spectroscopy (gas-microphone detection).The observation of cluster layers with TEM and high resolution SEM show small silver particles with diameters of about 50 nm (Fig. 1 and Figure 2, respectively). The electron diffraction patterns of homogeneous Ag layers and of cluster layers are similar, whereas the low loss EELS spectra due to plasmon excitation are quite different. Fig. 3 and Figure 4 show first results of EELS spectra of a cluster layer of small silver particles on carbon foil and of a homogeneous Ag layer, respectively.

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