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1.
The forward and reverse rate coefficients for the reactions (1) O2H+ + H2 ? H3+ + O2 and (2) O2D+ + D2 ? D3+ + O2 have been determined in a SIFT at 80 and 300 K, from which values of the enthalpy and entropy changes in the reactions have been obtained. The data indicate that the proton affinity of H2 is greater than that of O2 by 0.33 ± 0.04 kcal mole?1; similary, the deuteron affinity of D2 is 0.35 ± 0.04 kcal mole?1 greater than that of O2. The measurements of entropy changes confirm that O2H+ has a triplet electronic ground state.  相似文献   

2.
New anisotropic ESR spectra of Co2+ doped sapphire, different from hitherto known, are reported. The new spectra which are observed, beside the well-known spectra of α-Al2O3:Co2+, are shown to form two sets, each one consisting of six spectra (1–6) and (7–12). The spectra of both sets are proven to be interrelated by B3a symmetry. g and A tensors for each set will be given. Evidence is given that the two sets are to be assigned to the defects α-Al2O3:Co2+,H+ and α-Al2O3:Co2+,X+. The former is concluded to consists of a Co2+ ion at the substitutional site (c) and a proton located in a potential minimum along a straight line between O2- ions situated in O2+ triangles above and below the CO2+ ion. The potential function for the proton has been calculated by quantum-chemical calculations to clucidate the geometrical structure of the paramagnetic center. The α-Al2O3:Co2+,X+ could not be fully analyzed but some evidence is presented, that X+ might be alkali ions.  相似文献   

3.
Zusammenfassung Es wurde eine neue metallochrome Substanz, das 2-Bis(carboxymethyl)-aminomethyl-4(p-sulfophenyl)azo-naphthol synthetisiert, Methylnaphtholorange genannt. Ihre konsekutiven Dissoziationskonstanten wurden bestimmt, optimale Bedingungen ihrer Reaktion mit Ti4+, Sm3+ und UO 2 2+ aufgefunden, die Zusammensetzung der entstehenden Metallkomplexe festgestellt und die Bildungs- als auch Stabilitätskonstanten berechnet.
Summary A new metallochromic compound, 2-Bis(carboxymethyl)-aminomethyl-4(p-sulphophenyl)-azonaphthol, (named methylnaphthol orange) has been synthezised. Its consecutive dissociation constants have been determined, optimal conditions of its reactions with Ti4+, Sm3+ and UO 2 2+ worked out, the composition of the metal complexes identified and the constants of formation and stability have been computed.


Für technische Hilfe hei dieser Arbeit bin ich Herrn K. Haas dankbar.  相似文献   

4.
The geometrical parameters, normal vibration frequencies, and thermochemical characteristics of the Na2Cl+, NaCl 2 , Na3Cl 2 + , and Na2Cl 3 ions in saturated vapors over sodium chloride were calculated by the ab initio methods including electron correlation. According to calculations, the Na2Cl+ and NaCl 2 triatomic ions have a linear equilibrium D h configuration. The pentaatomic ions can exist in the form of the D h linear isomer, C 2v planar cyclic isomer, or D 3h bipyramidal isomer. At ∼1000 K the Na3Cl 2 + and Na2Cl 3 ions exist predominantly in the form of the linear isomers. The energies and enthalpies of the ion-molecule reactions involving the above ions were calculated. The formation enthalpy of the ions Δf H 0(0 K) was determined: 230 ± 2 kJ/mol (Na2Cl+), −96 ± 4 kJ/mol (Na2Cl 3 ), −616 ± 2 kJ/mol (NaCl 2 ), and −935 ± 4 kJ/mol (Na2Cl 3 ). Original Russian Text Copyright ? 2007 by T. P. Pogrebnaya, A. M. Pogrebnoi, and L. S. Kudin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 48, No. 6, pp. 1053–1061, November–December, 2007.  相似文献   

5.
Calcium and barium zirconate powders based upon CaZrO3:Eu3+,A and BaZrO3:Eu3+,A (A=Li+, Na+, K+) were prepared by combustion synthesis method and heating to ~1000℃ to improve crystallinity.The structure and morphology of materials were examined by X-ray diffraction (XRD) and scanningelectron microscopy (SEM). XRD results showed that CaZrO3:Eu3+,A and BaZrO3:Eu3+,A (A=Li+, Na+, K+) perovskites possessed orthorhombic and cubic structures, respectively. The morphologies of all powderswere very similar consisting of small, coagulated, cubical particles with narrow size distributions andsmooth and regular surfaces. The characteristic luminescences of Eu3+ ions in CaZrO3:Eu3+,A (A=Li+, Na+, K+) lattices were present with strong emissions at 614 and 625 nm for 5D07F2 transitions with other weakeremissions observed at 575, 592, 655, and 701 nm corresponding to 5D07Fn transitions (where n=0, 1, 3, 4 respectively). In BaZrO3:Eu3+ both the 5D07F1 and 5D07F2 transitions at 595 and 613 nm were strong.Photoluminescence intensities of CaZrO3:Eu3+ samples were higher than those of BaZrO3:Eu3+ lattices. Thisremarkable increase of photoluminescence intensity (corresponding to 5D07Fn transitions) was observedin CaZrO3:Eu3+ and BaZrO3:Eu3+ if co-doped with Li+ ions. An additional broad band composed of manypeaks between 440 to 575 nm was observed in BaZrO3:Eu3+,,A samples. The intensity of this band wasgreatest in Li+ co-doped samples and lowest for K+ doped samples.  相似文献   

6.
讨论了辛基(苯基)-N,N-二异丁基胺甲酰基甲基氧化膦(CMPO)/1-烷基-3-甲基咪唑双(三氟甲烷磺酰)亚胺盐([Cnmim][NTf2],n=2,8,12)萃取体系分别对硝酸溶液中的铕离子(Eu3+)和铀酰根离子(UO22+)的萃取行为。主要研究了硝酸浓度、接触时间、温度、CMPO浓度对CMPO/[Cnmim][NTf2]体系萃取性能的影响,并选取CMPO/[C2mim][NTf2]体系对模拟高放废液中的镧锕元素进行了萃取分离。结果表明:随着离子液体侧链长度增长,萃取平衡时间逐渐延长;CMPO/[C2mim][NTf2]体系对Eu3+的萃取是放热反应,萃取率随酸度增加而逐渐降低,对UO22+则是吸热反应,萃取率随酸度增加而逐渐升高;通过机理研究,推测出对Eu3+的萃取反应是离子交换,而对UO22+的萃取反应则是中性配位;CMPO/[C2mim][NTf2]体系能有效的萃取模拟高放废液中的镧系、锕系元素,且在高酸下有一定的镧锕分离效果。  相似文献   

7.
通过多步骤的化学法合成了Gd2O3:Yb3+,Nd3+,Tm3+/SiO2/Ag纳米复合材料。利用XRD,TEM,EDS,XPS,CLSM等方法对样品进行表征。实验结果表明,具有低声子能、稳定的化学性质的Gd2O3作为上转换发光的基质,当掺杂的敏化剂Nd3+离子浓度为1.0%(n/n),激活剂离子Tm3+浓度为0.5%(n/n)时,上转换发光强度达到最大值。此外,表面吸附的Ag纳米颗粒,由于表面等离激元共振耦合作用,使得上转换发光蓝光波段的强度增强1.70倍。  相似文献   

8.
The most stable conformation of ion-molecule complexes involving a CO molecule were surveyed by the use of Hartree-Fock (HF) MO and third-order Moller-Plesset perturbation (MP3) methods with a 6–31G* basis set ion = H+, Li+, Na+, K+, Bc2+, Mg2+, and Ca2+. The MP3 level of theory reveals the ion-CO conformation in which the ion bonds to a carbon atom of CO to be the most stable; these MP3 results are contrary to the HF ones. Binding energies of ion-molecule complexes involving CO and N2 were computed; MP3 energies are in good agreement with the experimental ones. The computed binding energies of cation-N2 are about one-third of cation-NH3 due to the absence of dipole moment and the smaller polarizability of N2. The decrease in binding energy in cation-CO and -N2 complexes, with increasing cation size, is mainly caused by the decrease of the electrostatic and polarization stabilizations.  相似文献   

9.
Electroinitiated production of NH2. radicals was demonstrated to occur in aqueous acid solution when in the system Cu2+/VO2+/NH2OH Cu2+ is reduced to metallic copper on a mercury cathode. The first stage of this process involves the reduction of vanadyl to V3+ by metallic copper. The electrochemical system Cu2+/VO2+ was demonstrated to follow a depolarization scheme of the type of the catalyzed electrode process.For the reaction Cu+2 VO2+k1Cu2++2 V3+ a k1 value of 32 M?1 s?1 at 50°C was calculated.The second stage of the process is the reduction of NH2OH by V3+ to give aminyl radicals. In presence of benzene and toluene these radicals add to the aromatic ring to give new radicals which are oxidized by Cu2+ to the corresponding amines.The cuzrent yield of this process attains values as high as 70%. The yield dependence on H2SO4 concentration, electrolytic current and dioxane concentration is discussed.  相似文献   

10.
Crayfish shell is an abundant natural waste and is also a potential biosorbent for pollutants, especially, heavy metals. In this study, the safety of the use of crayfish shell as a biosorbent was first assessed by release experiments involving primary heavy metal ions, such as Cu2+, Zn2+, and Cr3+, in aqueous solution under different environmental conditions. The release concentrations of heavy metals were dependent on pH, ionic strength, and humic acid; and the maximum release concentrations of heavy metals were still lower than the national standard. Specifically, Cu2+ and Pb2+ removal by crayfish shell in synthetic wastewater was investigated. The removal process involved biosorption, precipitation, and complexation, and the results indicate that crayfish shell is an excellent biosorbent for Cu2+ and Pb2+ removal. The precipitation step is particularly dependent on Ca species, pH, and temperature. The maximum removal capacities of Pb2+ and Cu2+ were 676.20 and 119.98 mg/g, respectively. The related precipitates and the generated complex products include Cu2CO3(OH)2, Ca2CuO3, CuCO3, Pb2CO3(OH)2, CaPb3O4, and PbCO3.  相似文献   

11.
综合ZnO-Al2O3-SiO2系和锗酸盐玻璃陶瓷的优点,采用熔融-晶化法首次制备了Ho3+/Yb3+共掺以ZnAl2O4为主晶相的ZnO-Al2O3-GeO2-SiO2系玻璃陶瓷。因[GeO4]四面体和[SiO4]四面体都是玻璃网络形成体,讨论了GeO2取代SiO2对玻璃陶瓷样品硬度及发光性能的影响,最终确定GeO2的取代量为10.55%(w/w)时,玻璃陶瓷综合性能最佳。在980 nm泵浦光的激发下,发现强的绿色(546 nm)和弱的红色(650 nm)上转换发光,并研究了不同Ho3+/Yb3+掺杂比对样品上转换发光的影响,最终结果表明当Ho3+/Yb3+掺杂比为1:11(n/n)时样品荧光强度最强,在绿色上转换发光材料方面具有潜在的应用。  相似文献   

12.
采用sol-gel法合成了系列发光体Li2O-Ln2O3-SiO2:Eu^3^+,Bi^3^+,并确定了发光体的物相结构。当Ln^3^+=Y^3^+和Ln^3^+=La^3^+时,紫外光激发下Eu^3^+的发射分别以红光和橙光为主,只存在一种Eu^3^+发光中心;Ln^3^+=Gd^3^+时,至少存在两种Eu^3^+发光中心和两种Bi^3^+发光中心(共掺杂Eu^3^+,Bi^3^+的吸收和发射所  相似文献   

13.
将过渡金属配合物阳离子([M(DETA)2]n+(M=Cu2+,Ni2+,Co3+;DETA=Diethylenetriamine,二乙烯三胺)作为客体插入层状MnPS3层间得到了相应的3个夹层化合物。通过X-射线粉末衍射、元素分析和红外光谱对夹层化合物的结构进行了表征。结果表明,与主体MnPS3 0.65 nm的层间距相比较,夹层化合物(Mn0.88PS3[Cu(DETA)2]0.12)的层间距扩大了0.32 nm,由此推测客体[Cu(DETA)2]2+在层间以平面四方的配位形式存在,而另2个夹层化合物(Mn0.79PS3[Ni(DETA)2]0.21和Mn0.74PS3[Co(DETA)2]0.17)的层间距扩大了0.48 nm,说明客体[(M(DETA)2]n+,M=Co3+,Ni2+) 在主体层间以八面体配位形式存在。磁性测试结果表明过渡金属离子[(M(DETA)2]n+(M=Cu2+,Co3+)的插入能引起主体MnPS3的磁性在35~40 K发生由顺磁向亚铁磁性的转变并表现自发磁化,而客体[Ni(DETA)2]2+却使夹层化合物的反铁磁相互作用增强,抑制了自发磁化的发生。  相似文献   

14.
Cation fluxes from binary mixtures of either Na+, Cs+ or Sr2+ with other alkali metal cations, alkaline earth metal cations, and Pb2+ through a H2OCHCl3H2O bulk liquid membrane system containing one of several macrocyclic carriers have been determined Nitrate salts were used in all cases. The most selective transport of Na+ over all other cations studied was found with the carrier cryptand [2.2.1]. Selective transport of Na+ relative to Li+, Cs+ and the alkaline earth cations was found with cryptand [2.2.2B] and cryptand [2.2.2D]. The ligands 21-crown-7 and dibenzo-24-crown-8 showed selective transport of Cs+ over the second cation in all cases. Several macrocycles showed selectivity for Sr2+ over the second cation with the macrocycle 1,10-diaza-18-crown-6 showing the highest selectivity for this cation of all ligands studied. Relative fluxes from binary cation mixtures are rationalized in terms of macrocycle cavity size, donor atom type and ring substituents.  相似文献   

15.
The behaviour in aqueous solution of some aminocarboxylates of the type NH2(CH2)nS(CH2)m-1COO? (abbreviated as n,m-NSO; n and m = 2 or 3) in equilibria with H+, Cu2+ and Ni2+ ions has been investigated potentiometrically and calorimetrically at 25° C in a 0.5 M KNO3 medium.The protonation of the amino function and especially the carboxylate function is attended by strong desolvation effects, which are characterized by low exothermic enthalpies and strongly positive entropies of protonation.In [Cu(n,m-NSO)]+ and [Ni(n,m-NSO)]+ the aminocarboxylates act as tridentate ligands, forming complexes with a strong hard—hard character. The biligand species [Ni(n,m-NSO)2] behave as six-coordinated complexes whereas in [Cu(n,m-NSO)2] the second ligand is bound only through the N and S donor, forming a five-coordinated species.Finally, the n,m-NSO ligands also form protonated species with the Cu2+ ion.  相似文献   

16.
采用微波固相法制备了CaWO4xEu3+,ySm3+,zLi+红色荧光粉。测量样品的XRD图、激发谱、发射谱及发光衰减曲线,研究并分析了Eu3+、Sm3+、Li+的掺杂浓度,对样品微结构、光致发光特性、能量传递及能级寿命的影响。结果表明,Eu3+、Sm3+、Li+掺杂并未引起合成粉体改变晶相,仍为CaWO4单一四方晶系结构。Eu3+、Sm3+共掺样品中,Sm3+掺杂为3%时,Sm3+对Eu3+的能量传递最有效。Li+掺杂起到了助熔剂和敏化剂的作用,使样品发光更强。在394 nm激发下,与CaWO4:3%Eu3+样品比较,3%Eu3+、3%Sm3+共掺CaWO4及3%Eu3+、3%Sm3+、1%Li+共掺CaWO4样品的发光分别增强2倍及2.4倍。同一激发波长下,单掺Eu3+样品寿命最短,Sm3+、Eu3+共掺样品随Sm3+浓度增加,寿命先减小后增加,且掺杂了Li+的样品比不掺Li+的样品5D0能级寿命有所增加。  相似文献   

17.
The recombination energy of N22+ has been computed using N22+, N22+ and N2 potential curves from the literature. Vibrational overlaps and energies liberated in the various N22+3?g,1g+, 3Πu, 1Πu → N2+(X2+g, A 2+g, A 2Πu, B2u+,C2u+) vibronic transitions have been computed and used as input for determination of the N2+ recombination energy.  相似文献   

18.
Luminescence emission and uv-excitation properties of LaOBr: Tb3+, LaOBr: Ce3+, and LaOBr: Tb3+, Ce3+ phosphors were studied. The visible emission spectra of La0.995Tb0.005OBr consists of5D3,47F3–6 transitions in the wavelength range of 410–630 nm. The excitation of the Tb3+ ion gives a broad 4f → 5d transition band at 254 nm and weaker4f → 4f transition lines above 300 nm. The uv-excitation and emission of La0.995Ce0.005OBr at 290, 315, 355 (excitation), and 440 nm (emission) originate from transitions between the 4f-ground state and the four crystal field components of the5d2D excited state. The sensitization of Tb3+ luminescence in LaOBr with Ce3+ at varying concentrations is described and discussed. With increasing Ce3+ concentration the 5D37F transitions of Tb3+ quench totally and the5D47F transitions begin to quench gradually. The excitation spectrum of the5D47F5 transition of Tb3+ consists of four bands due to Tb3+ and Ce3+, of which the three Ce3+ bands increase in intensity and the Tb3+ band decreases as the Ce3+ concentration is increased.  相似文献   

19.
以P123为表面活性剂,异丙醇铝为铝源,用简易溶胶-凝胶法,获得了单掺和双掺Gd3+,Eu3+的介孔氧化铝组装体。用广角X-射线衍射仪(WAXD)进行了物相分析;小角X-射线衍射仪(SAXD)、比表面仪进行了孔结构分析和形貌表征;研究了组装体的发光性能并发现Gd3+对Eu3+有能量传递作用,并分析了能量传递过程。  相似文献   

20.
Single crystals of Ca2+, Sr2+, Ba2+, and Pb2+ beta″ alumina were prepared from sodium beta″ alumina by ion exchange. The ionic conductivities of Ca2+, Sr2+, and Ba2+ beta″ alumina are comparable, about 3 × 10?2 (ohm-cm)?1 at 300°C. Surprisingly, Pb2+ beta″ alumina is much more conductive, 1.5 × 10?1 (ohm-cm)?1 at 300°C and 4.6 × 10?3 (ohm-cm)?1 at 40°C. Its conductivity approaches that of sodium beta″ alumina at temperatures below 25°C. The diffusion coefficient for Sr2+ in beta″ alumina at 600°C was estimated from radiotracer experiments. It is consistent with that expected from conductivity measurements.  相似文献   

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