992 resultados para Yb^3
Resumo:
La2O3YbY2O3La2O3YbY2O3La^3Y^3Y2O3La^3Y2O3Y2O3La2O3x=016yb^3La2O345-60.
Resumo:
1234N_(1923)Zn(II)Cd(II)Re(III)N_(1923)ZnCl_2CdCl_2Zn(SCN)_2N_(1923)HPMBPREIIIN_(1923)Sc(III)N_(1923)(TBP, DBBP)Zn(II)Cd(II)1. N_(1923)TBPDBBPZnCl_2 N_(1923)TBPDBBPZnCl_2(RNH_3Cl)_3ZnCl_2B(RNH_3Cl)_2ZnCl_2B (B = TBPDBBP)ZnCl_2 + (RNH_3Cl)_3_((o)) + TBP_((o)) ~(K_(12)(TBP) (RNH_3Cl)_3ZnCl_3ZnCl_2TBP_((o)) ZnCl_2+Z/3(RNH_3Cl)_(3(o)) + DBBP_((o)) (RNH_3Cl)_2 ZnCl_2DBBP_((o))(RNH_3Cl)_3ZnCl_(2(o)) + TBP_((o))~(B_(12)(TBP) (RNH_3Cl)_3ZnCl_2TBP_((o)) (RNH_3Cl)_3ZnCl_(2(o)) + DBBP_((o)) ~(B_(12)(DBBP) (RNH_3Cl)_2ZnCl_2DBBP_((o)) + RNH_3Cl_((o))Zn(II)DBBP>TBPDD_1/DD_IRNMR2.N_(1923)TBPZn_(SCN)_2N_(1923)TBPZn(SCN)_2TBPZn(SCN)_2N_(1923)TBPZn(SCN)_2Zn(SCN)_23TBP. (RNH_3)_2Zn(SCN)_4TBP,Zn(SCN)_4~(2-) + (RNH_3NO_3)_(2(o)) + TBP_((o)) (RNH_3)_2Zn(SCN)_4TBP_((o)) + 2NO_3~-(RNH_3)_2Zn(SCN)_(4(o)) + TBP_((o)) ~(B'12) (RNH_3)_2Zn(SCN)_4TBP_((o)) (a) (RNH_3NO_3)_(2(o)) + Zn(SCN)_23TBP_((o)) + 2SCN~-~("12)(RNH_3)Zn(SCN)_4TBP_((o))+2TBP_((o))+2NO_3~- (b) (RNH_3NO_3)_(2(o)) + (RNH_3)_2Zn(SCN)_(4(o)) + 2SCN~- + Zn(SCN)_2.3TBP_((o)) ~("12)R(RNH_3)_2Zn(SCN)_4.TBP_((o)) + 2NO_3~- + TBP_((o)) (c) "'_(12) > '_(12) > "_(12)cabSCN~- > Cl~_IR3. N_(1923)TBPDBBPCdIIN_(1923)TBPDBBPCd(II)(RNH_3Cl)_2CdCl_2BCdCl_2 + 2/3 (RNH_3Cl)_(3(o)) + B_((o)) ~(K_(12)) (RNH_3Cl)_2CdCl_2B_((o)) (RNH_3Cl_3)CdCl_2_((o)) + B_((o)) ~(BR)(RNH_3Cl)_2CdCl_2B_((o)) + RNH_3Cl_((o))Zn(II)Zn(II) > Cd(II)IRNMR. N_(1923)HPMBPREIIIN_(1923)HPMBPREIIIRE~(3+ = La~(3+), Pr~(3+), Eu~(3+), Gd~(3+), Tb~(3+), Er~(3+), Yb~(3+)Y~(3+)RNH_3Ln(PMBP)_4Pr(III)Ln~(3+) + 4HPMBP_((o)) + RNH_3Cl_((o)) RNH_3LN(PMBP)_(4(o)) + 4H~+ + Cl~- Ln(PMBP)_(3(o)) + RNH_3Cl_((o)) RNH_3Ln(PMBP)_(4(o)) + H~+ + Cl~- RZRNH_3ClPr(III)IRNMRN_(1923)Sc(III)RNH_3NO_3Sc(III)Sc(OH)_2~+SCN~-, NO_3~-RNH_3nO_3Sc(III)PHSc(OH)_2~+ + SCN~- + 2(RNH_3NO_3)_(2((o)) (RNH_3nO_3)_4.Sc(OH)_2SCN_((o)) Sc(OH)_2~+ + SCN~- + NO_3~- + (RNH_3NO_3)_(2(o)) (RNH_3NO_3)_2.Sc(OH)(SCN)NO_3 + OH~-
Resumo:
Reaction of 3-(2-pyridylmethyl)indenyl lithium (1) with LnI(2)(THF)(2) (Ln = Sm, Yb) in THF produced the divalent organolanthanides (C5H4NCH2C9H6)(2)Ln(II)(THF) (Ln = Sm (2), Yb (3)) in high yield. 1 reacts with LnCl(3) (Ln = Nd, Sm, Yb) in THF to give bis(3-(2-pyridylmethyl)indenyl) lanthanide chlorides (C5H4NCH2C9H6)(2)Ln(III)Cl (Ln = Nd (4), Sm (5)) and the unexpected divalent lanthanides 3 (Ln = Yb). Complexes 2-5 show more stable in air than the non-functionalized analogues. X-ray structural analyses of 2-4 were performed. 2 and 3 belong to the high symmetrical space group (Cmcm) with the same structures, they are THF-solvated 9-coordinate monomeric in the solid state, while 4 is an unsolvated 9-coordinate monomer with a trans arrangement of both the side-arms and indenyl rings in the solid state. Additionally, 2 and 3 show moderate polymerization activities for F-caprolactone (CL).
Resumo:
~(13)C NMRHo~(3+)Yb~(3+),,,,,,C1-C2-C5-C6,C2-N-C3-C4C2-C5-C6-C8,C2-C5-C6-C7C1-C2-N-C3
Resumo:
The mechanism of the Yb(3+)-->Er(3+) energy transfer as a function of the donor and the acceptor concentration was investigated in Yb(3+)-Er(3+) codoped fluorozirconate glass. The luminescence decay curves were measured and analyzed by monitoring the Er(3+)((4)I(11/2)) fluorescence induced by the Yb(3+)((2)F(5/2)) excitation. The energy transfer microparameters were determined and used to estimate the Yb-Er transfer rate of an energy transfer process assisted by excitation migration among donors state (diffusion model). The experimental transfer rates were determined from the best fitting of the acceptor luminescence decay obtained using a theoretical approach analog to that one used in the Inokuti-Hirayama model for the donor luminescence decay. The obtained values of transfer parameter gamma [gamma(exp)] were always higher than that predicted by the Inokuti-Hirayama model. Also, the experimental transfer rate, gamma(2)(exp), was observed to be higher than the transfer rate predicted by the migration model. Assuming a random distribution among excited donors at the initial time (t=0) and that a fast excitation migration, which occurs in a very short time (t<gamma(-2)), reducing the mean distance between donor (excited) and acceptor, all the observed results could be explained. (C) 2003 American Institute of Physics.
Resumo:
In this paper, we report luminescent and morphological studies with yttrium oxide samples doped with ytterbium and erbium. The samples were prepared by the combustion method and also from different precursors: oxalate, basic carbonate and polymeric resin. All powders were identified Lis being an yttrium oxide with a C-form structure, independent of the employed precursor. From mean crystallite size measurements, it was verified that oxides prepared through the polymeric precursor and combustion methods lead to the smallest crystallite size. Particle shape and size were investigated by SEM and TEM, and showed that both the oxalate precursor and the combustion methods do not provide oxide materials of suitable shape or size, on the other hand. The basic carbonate and polymeric precursors resulted in spherically shaped particles with an average diameter of 90 and 15 run. respectively, Upon 980 run diode laser excitation, green and red emission lines were detected for all samples and were assigned to the H-2(11/2) S-4(3/2) -> I-4(15/2) and (4)Fg(9/2) -> 4I(15/12) transitions, respectively. Such transitions are characteristic for Er3+ and result from energy transfer from Yb3+ energy levels, F-2(7/2) -> F-2(5/2). A relationship between the decrease in the mean crystallite size and the enhancement in red emission was also established as well as the influence of the presence of a high percentage of Yb-3 Both factors promote ET from Yb3+ (F-2(5/2)) to Er3+ (I-4(11/2)). (c) 2004 Elsevier B.V. All rights reserved.
Resumo:
To optimize the performance of longitudinally pumped Yb^(3+):Y2O3 ceramic lasers, cavity parameters such as material length and output coupler transmission at a certain laser output power are calculated numerically using quasi-three-level laser model. The results show great potential of Yb^(3+):Y2O3 ceramics for highly efficient diode-pumped solid-state lasers.
Resumo:
Er^3+Tm^3+/Yb^3+Raman980nmLD(476nm)(530nm545nm)(656nm)(476nm)Tm^3+1^G43^3H6(530nm545nm)Er^3+2^H11/24^I1524^S3/24^I15/2(6
Resumo:
Er^3/Yb^3. , McCumberEr^31533 nm0.8410^-20 cm^2, ^4I13/28.5 ms. , Er^3/Yb^3. , 80 mW, 16.5%.
Resumo:
Yb^3+-Er^3+P2O5-B2O3-R2O-MO-Al2O3(R=LiNaKM=ZnCaSrBa)B2O3B2O3TgTf
Resumo:
An interesting fluorescence intensity reverse photonic phenomenon between red and green fluorescence is investigated. The dynamic range. of intensity reverse between red and green fluorescence of Er( 0.5) Yb( 3): FOV oxyfluoride nanophase vitroceramics, when excited by 378.5nm and 522.5nm light respectively, is about 4.32 x 10(2). It is calculated that the phonon- assistant energy transfer rate of the electric multi- dipole interaction of {(4)G(11/2)( Er3+) -> F-4(9/2)( Er3+), F-2(7/2)( Yb3+). F-2(5/2)( Yb3+)} energy transfer of Er( 0.5) Yb( 3): FOV is around 1.380 x 10(8) s(-1), which is much larger than the relative multiphonon nonradiative relaxation rates 3.20 x 10(5) s(-1). That energy transfer rate for general material with same rare earth ion's concentration is about 1.194 x 10(5) s(-1). These are the reason to emerge the unusual intensity reverse phenomenon in Er( 0.5) Yb( 3): FOV. (C) 2007 Optical Society of America.
Resumo:
Infrared-to-visible upconversion fluorescence of Er(3+)/Yb(3+) co-doped lithium-strontium-lead-bismuth (LSPB) glasses for developing potential upconversion lasers has been studied under 975-nm excitation. Based on the results of energy transfer efficiency and upconversion spectra, the optimal Yb(3+)-Er(3+) concentration ratio is found to be 5:1. Intense green and red emissions centered at 525, 546, and 657 nm, corresponding to the transitions 2H_(11/2)-->4I_(15/2), 4S_(3/2)-->4I_(15/2), and 4F_(9/2)-->4I_(15/2), respectively, were observed. The quadratic dependence of the 525-, 546-, and 657-nm emissions on excitation power indicates that a two-photon absorption process occurs under 975-nm excitation. The high-populated 4I_(11/2) level is supposed to serve as the intermediate state responsible for the upconversion processes. The intense upconversion luminescence of Er(3+)/Yb(3+) co-doped LSPB glasses may be a potentially useful material for developing upconversion optical devices.
Resumo:
The thermal stability, Raman spectrum and upconversion properties of Tm^(3+)/Yb^(3+) co-doped new oxyfluoride tellurite glass are investigated. The results show that Tm^(3+)/Yb^(3+) co-doped oxyfluoride tellurite glass possesses good thermal stability, lower phonon energy, and intense upconversion blue luminescence. Under 980-nm laser diode (LD) excitation, the intense blue (475 nm) emission and weak red (649 nm) emission corresponding to the 1G4 -> 3H6 and 1G4 -> 3F4 transitions of Tm^(3+) ions respectively, were simultaneously observed at room temperature. The possible upconversion mechanisms are evaluated. The intense blue upconversion luminescence of Tm^(3+)/Yb^(3+) co-doped oxyfluoride tellurite glass can be used as potential host material for the development of blue upconversion optical devices.
Resumo:
A new Er(3+)/Yb(3+) co-doped phosphate glass has been prepared, which exhibits good chemical durability and spectralproperties. Planar graded index waveguides have been fabricated in the glass by (Ag+)-Na(+) ion exchange in a mixed melt of silver nitrate and potassium nitrate. Ion exchange is carried out by varying the process parameters such as temperature, diffusion time, and molten salt compositions. The diffusion parameters, diffusion coefficients, and activation energy are determined by the guidelines of fabricated waveguides, which are determined by the input prism coupling technique.
