Delayed emission from organic mixed crystals: Phosphorescence spectrum of biphenyl guest‐carbazole host mixed crystal

1973 ◽  
Vol 59 (5) ◽  
pp. 2409-2414 ◽  
Author(s):  
T. N. Misra ◽  
Krishnagopal Mandal
Keyword(s):  
Mixed Crystal ◽  
Phosphorescence Spectrum ◽  
Mixed Crystals

The electronic spectra of mixed crystals

1963 ◽  
Vol 271 (1345) ◽  
pp. 207-217 ◽  
Keyword(s):  
Intermolecular Interactions ◽  
Electronic Spectra ◽  
Mixed Crystal ◽  
Electronic States ◽  
Dipole Approximation ◽  
Mixed Crystals ◽  
Excited Electronic States ◽  
Guest Molecules ◽  
Rough Approximation ◽  
Crystal Properties

The excited electronic states of dilute mixed crystals are discussed in terms of the theory of intermolecular interactions in dipole-dipole approximation. Resonance interactions of the Davydov type, which are of the first importance in pure crystals, are absent. However, interactions between host and guest molecules are generally of com parable importance to second-order interactions in pure crystals, and lead to similar changes in absolute absorption intensities and polarization ratios. There is a substantial departure from oriented-gas behaviour, which can be regarded as only a rough approximation to mixed crystal properties.

Tuning of the exchange interaction and the Curie temperature by mixed crystal formation of the bridging anionic ligands

2019 ◽  
Vol 55 (18) ◽  
pp. 2652-2655 ◽  
Author(s):  
Tristan Neumann ◽  
Michał Rams ◽  
Zbigniew Tomkowicz ◽  
Inke Jess ◽  
Christian Näther
Keyword(s):  
Critical Temperature ◽  
Curie Temperature ◽  
Exchange Interaction ◽  
Coordination Polymers ◽  
Mixed Crystal ◽  
Mixed Crystals ◽  
Exchange Constant ◽  
Crystal Formation ◽  
Anionic Ligands ◽  
Mixed Crystal Formation

A strategy to continuously tune the exchange constant J and the critical temperature Tc in the 1D coordination polymers [Co(NCS)x(NCSe)2−x(pyridine)2]n is reported. For such mixed crystals, prepared by annealing and from solution, an increase of J and Tc with increasing selenocyanate content is observed.

THE REFLECTIVITY OF THE MIXED CRYSTAL AB1-xCx

2010 ◽  
Vol 24 (27) ◽  
pp. 5337-5343
Author(s):  
XIAOYAN ZHANG ◽  
JINGFENG WANG ◽  
GUOLIANG FAN
Keyword(s):  
Mixed Crystal ◽  
Random Element ◽  
Mixed Crystals ◽  
Phonon Interaction ◽  
Long Wavelength ◽  
Electron Phonon Interaction ◽  
The Third ◽  
Optical Character ◽  
Mode Behavior ◽  
The One

The properties of long wavelength optical phonons in mixed crystals AB 1-x C x is discussed by a model similar to Modified Random Element Isodisplacement (MREI). Using this method we investigate the frequencies, the dielectric functions, and the reflectivity of several mixed crystals. It is found that this model can be applied to the one-mode behavior, the two-mode behavior, and that of the third category. So the model provides a possible way to understand the optical character of the ternary mixed crystal. Based on it, we can discuss other problems similar to electron–phonon interaction and so on.

Über Erdalkalimetalloxogallate, VI Zum Problem der Mischkristallbildung zwischen CaGa2O4 und CaAl2O4 / On Alkaline Earth Metal Oxogallates, VI About Mixed Crystal Formation of CaGa2O4-CaAl2O4

1976 ◽  
Vol 31 (12) ◽  
pp. 1604-1606 ◽  
Author(s):  
Hk. Müller-Buschbaum ◽  
W. Schmachtel
Keyword(s):  
Single Crystal ◽  
Alkaline Earth ◽  
Mixed Crystal ◽  
Earth Metal ◽  
Mixed Crystals ◽  
Alkaline Earth Metal ◽  
Crystal Formation ◽  
X Ray ◽  
Mixed Crystal Formation

Mixed crystals of the formulae CaGaAlO4 (1) and CaGa0.5Al1.5O4 (2) were investigated by X-ray single crystal work. 1 shows a tetrahedral orientation like that of CaGa2O4 (monokl.), 2 another one of CaAl2O4. A discussion of the different polyhedral arrangement of the stuffed tridymite structures is given.

The thermodynamics of mixed crystals of ammonium chloride and ammonium bromide. - III. The heat capacity from 8 to 300 K of solid solutions of composition NH 4 Br 0.20 Cl 0.80 and NH 4 Br 0.74 Cl 0.26

1981 ◽  
Vol 375 (1762) ◽  
pp. 351-359
Keyword(s):  
Heat Capacity ◽  
Ammonium Chloride ◽  
Solid Solutions ◽  
Mixed Crystal ◽  
Mixed Crystals ◽  
Ammonium Bromide ◽  
Ammonium Ions ◽  
Β Phase ◽  
Δ Phase ◽  
Entropy Of Transition

The heat capacity of the mixed crystals NH 4 Br 0.20 CI 0.80 and NH 4 Br 0.74 CI 0.26 has been measured from ca . 8 to 300 K. The first of these solids has, as expected, two gradual transitions, the lower having an entropy of transition ∆ S λ of 3.79 J K –1 mol –1 , and the upper a ∆ S λ of 4.51 J K –1 mol –1 . The heat capacity between these two transitions is always considerably above the ‘normal’ or baseline value, and it appears that the orientational disordering of the ammonium ions, while completed in the γ → β transition, commences in the δ-phase. The other, bromide-rich mixed crystal shows no sign of a δ → γ transition, but has a λ -type γ → β transition which culminates at 262.5 K, with ∆ S λ = 7.31 J K –1 mol –1 . The heat capacity of both mixed crystals in the β-phase, like that of the pure components, is ‘anomalously’ high, the additional heat capacity for the solid solutions being larger than that for the pure salts. The phase diagram for the ammonium-chloride–ammonium-bromide system is shown; it combines previous information with that provided by the heat-capacity results reported in this and previous papers.

Roentgenographic and thermodynamic study of the existence of mixed crystals in the LaC2-YC2 system

1985 ◽  
Vol 50 (5) ◽  
pp. 1153-1160 ◽  
Author(s):  
Bohumil Hájek ◽  
Vladimír Kohout ◽  
Vratislav Flemr
Keyword(s):  
Diffraction Study ◽  
Carbothermal Reduction ◽  
Mixed Crystal ◽  
Mixed Crystals ◽  
Crystal Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrolysis Products ◽  
Mixed Crystal Formation ◽  
Gas Pressures

The reaction heats for the mixed crystal formation in the LaC2-YC2 system were obtained from the equilibrium gas pressures measured during the carboreduction. The low positive values of the reaction heats are consistent with the X-ray diffraction study of the carbothermal reduction products of the oxides, where the formation of the (La, Y)C2 dicarbide mixed crystals was only observed in the two side regions up to 25 mol.% of each of the minority components. The composition of the gaseous hydrolysis products of the (La, Y)C2 mixed crystals corresponds to the hydrolysis products of the dicarbide. No methane was detected for samples with low yttrium contents.

Spectroscopic and Magnetostructural Evidence for the Formation of [Cu0.5Co0.5(H2Tea)X] Mixed-Crystal Compounds from Zerovalent Cu and Co Salts in the Presence of Triethanolamine (H3Tea -Triethanolamine; X = SCN, Cl)

2001 ◽  
Vol 56 (9) ◽  
pp. 931-936 ◽  
Author(s):  
Valeriya G. Makhankova ◽  
Olga Yu. Vassilyeva ◽  
Volodymyr N. Kokozay ◽  
Brian W. Skelton ◽  
Gerard A. Van Albada ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Atomic Absorption ◽  
Preliminary Report ◽  
Mixed Crystal ◽  
Metallic Copper ◽  
Electronic Spectroscopy ◽  
Mixed Crystals ◽  
Molar Ratio ◽  
Simultaneous Presence ◽  
Trigonal Bipyramidal

Mixed crystals [Cu0.5Co0.5(H2Tea)(SCN)] (1), [Cu0.5Co0.5(H2Tea)Cl] (2) (H3Tea = triethanolamine) have been obtained by the open-air reaction of metallic copper with cobalt(II) chloride/cobalt(II) thiocyanate and triethanolamine in non-aqueous solvents, like dmf, dmso, CH3OH and CH3CN. The simultaneous presence of copper and cobalt in the mixed crystals was unambiguously determined by atomic absorption, EPR and electronic spectroscopy. Details of 1 have been studied structurally, and a preliminary report of the structure of 2 is also given. The mononuclear species 1 and 2 contain crystallographically indistinguishable Cu(II) and Co(II) ions in virtually identical trigonal bipyramidal sites. The molecules are linked together by O-H···O hydrogen bonds to give chains. The values of the temperature independent μeff of 3.50 and 3.48 μB for 1 and 2 (in the range of T = 20 - 280 K), respectively, agree with the 1:1 molar ratio of the metals in both samples.

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