Eu^2＋：Sr9Ca（PO4）6Cl2中的新型色心及其光激励发光

本文报道了Ｅｕ＾２＋：Ｓｒ９Ｃａ（ＰＯ４）６Ｃｌ２的新型色心。它的吸收带主峰分别位于７０８，７８５，８４５及９９０ｎｍ。用对应于Ｆ心吸收带和这些吸收带波长的光束分别激励样品时得到相同的光激励发光。通过对比研究表明，这些吸收带是由Ｆ心的缔合中心，即由ＦＡ心产生的。由于这些色心的吸收带偏离Ｅｕ＾２＋的发射波长（４５０ｎｍ）更远，故更适应于Ｅｕ＾２＋：Ｓｒ９Ｃａ（ＰＯ４）６Ｃｌ２光波励发光的研究和开发。     

MAl2O4：Eu^2＋,RE^3＋,长余辉发光性质的研究

研究鳞石英结构碱土铝酸盐ＭＡｌ２Ｏ４：Ｅｕ＾２＋,ＲＥ＾＋（Ｍ＝Ｍｇ,Ｃａ,Ｓｒ,Ｂａ：ＲＥ＝Ｙ,Ｌａ,Ｃｅ,Ｐｒ,Ｎｄ,Ｓｍ,Ｇｄ,Ｔｂ,Ｄｙ,Ｈｏ,Ｅｒ,Ｔｂ,Ｄｙ,Ｈｏ,Ｅｒ,Ｔｍ,Ｙｍ,Ｙｂ,Ｌｕ）的荧光及长余辉发光性质。其发光由Ｅｕ＾２＋的４ｆ－５ｄ跃迁产生。ＲＥ＾３＋作为辅助激离子,提供合适的陷阱能级。即使用ＲＥ＾３＋的特性波长激发,在ＭＡｌ２Ｏ４：Ｅｕ＾３＋的发光中也观察不到ＲＥ＾３     

Ca8Mg(SiO4)4Cl2中Ce3+和Eu2+的光谱性质和能量传递

首次合成了Ｃｅ＾３＋和Ｅｕ＾２＋共激活氯硅酸镁钙Ｃａ８Ｍｇ（ＳｉＯ４）４Ｃｌ２：Ｃｅ＾３＋，Ｅｕ＾２＋高效绿色荧光粉，报道了它们的漫反射光谱、激发和发射光，观察到氯硅酸镁钙中Ｃｅ＾３＋ Ｅｕ＾２＋     

SrAl2O4：Eu^2＋,Dy^3＋荧光材料的发光性质

我们在本文中制作了五种不同ＳｒＡｌ２Ｏ４：Ｅｕ＾２＋和Ｄｙ＾３＋的样品。样品分别是ＳｒＡｌ２Ｏ４基质的α相和β相的粉末和片状样品,以及单晶样品。我们对所有样品进行了形貌的ＳＥＭ研究。我们还对α相和β相粉末样品及片状样品以及α相单晶样品的荧光发射谱进行了测量。它们的荧光发射的中心波长为５２０ｎｍ,对应于ＳｒＡｌ２Ｏ４基质中的Ｅｕ＾２＋的４ｆ＾６５ｄ＾１的＾２ｅｇ激发态到４ｆ＾７的＾８Ｓ７／２的跃迁发     

X射线辐照下BaF_xCl_（2－x）：Eu~（2＋）的热释发光性质

本文研究了在不同温度下，经互射线辐照后ＢａＦｘＣｌ２－ｘ：ＥＵ２＋的热释发光性质．给出了热释发光峰的温度与缺陷种类的关系，讨论了两种温度辐照下，ＢａＦｘＣｌ２－ｘ：Ｅｕ２＋（Ｘ＝０．９０，…，１．１５）热释发光产生差异的原因．     

Eu3+:Y2SiO5晶体透射光谱和荧光谱研究

在室温条件下,对Ｅｕ＾３＋：Ｙ２ＳｉＯ５晶体的透射光谱和４５７．９ｎｍＡｒ＾＋激光激发荧光谱进行测量和研究。这些光谱表明,Ｅｕ＾３＋离子在Ｙ２ＳｉＯ５晶体中占据两种最低对称性Ｃ１格位。利用透射光谱和荧光谱对Ｅｕ＾３＋离子的最低激发态＾５Ｄ０的两种格位光谱进行了成功分离。实验发现,在＾５Ｄ０态两种格位谱的谱宽只有０．１ｎｍ左右,其峰间隔约为０．１８ｎｍ。另外,文中还测量了Ｅｕ＾３＋离子的基态＾７ＦＪ     

CuSO4·5H2O在用KBr压片法制样时所发生的固相反应的研究

用Ｘ射线衍射法和ＦＴ－ＩＲ法研究了ＣｕＳＯ４·５Ｈ２Ｏ在用ＫＢｒ压片法制样过程中所发生的固相反应．主要产物为：Ｋ２Ｃｕ（ＳＯ４）２·６Ｈ２Ｏ和ＣｕＢｒ２。     

BaFBr，BaFBr：Eu~（2＋）和BaFBr：Ce~（3＋）晶体在X射线辐照和光激励过程中发光和光电导的实时原位测量

在自建的多功能实时原位测量发光特性和光电导的实验装置上，测量了ＢａＦＢｒ，ＢａＦＢｒ：Ｅｕ２＋和ＢａＦＢｒ：Ｃｅ３＋单晶在Ｘ射线辐照和光激励过程中的发光强度和光电导。首次从光电导的角度测量到Ｘ射线辐照时，Ｅｕ２＋并没有被离化，而Ｃｅ３＋被离化，离化电子经导带被Ｆ＋心俘获；明确证实了光激励过程中Ｆ心电子的隧穿效应。     

F／Cl比与Eu~（2＋）：BaFCl中F色心的浓度和光激励截面的关系

研究了Ｅｕ（２＋）：ＢａＦｘＣｌ２在紫外线辐照下的光激励发光。通过改变激励方式及激励光的扫描方向，给出了Ｅｕ（２＋）：ＢａＦｘＣｌ２－ｘ光激励发光过程中，两种Ｆ色心的浓度比值与光激励截面比值的测定方法。利用这种测定方法，进一步研究了两种Ｆ色心的浓度比值和光激励截面比值与Ｆ／ＣＩ比值的关系。     

H2O＋Cl→HCl＋OH反应中D同位素的动力学效应的理论研究

根据传统过渡态，变分过渡理论计算了Ｈ２Ｏ＋Ｃｌ→ＨＣｌ＋ＯＨ（Ｒ１）反应中Ｄ代替的同位素动力学效应（ＫＩＥ）得到了ＨＯＤ＋Ｃｌ→ＤＣｌ＋ＯＨ（Ｒ２），ＤＯＨ＋Ｃｌ→ＨＣｌ＋ＯＤ（Ｒ３）反应不同的ＫＩＥ值，对ＫＩＥ进行了分解，讨论了平动（ｔｒａｒｓ）转动（ｒｏｔ）振动（ｖｉｂ）等各种因素的作用，在反应Ｒ２中，由于ＨＯＤ中ＯＤ键直接参与反应，Ｄ同位素的ＫＥ很大，对Ｒ２的ＫＩＥ分解表明，振动对ＫＩＥ贡献     

Magnetic ordering in HoRu2Si2, HoRh2Si2, TbRh2Si2 and TbIr2Si2 by neutron diffraction

Neutron diffraction study of polycrystalline HoRu₂Si₂, HoRh₂Si₂, TbRh₂Si₂, and TbIr₂Si₂ was performed in the temperature range between 4.2 and 300 K. For HoRu₂Si₂ the magnetic spin alignment of a linear transverse wave mode below the Néel temperature 19 K is observed. This static moment wave is propagating along the b-axis with k=(0, 0.2, 0) and is polarized in the c-axis. The root-mean-square and maximum saturation moments per Ho atom are 9.26 and 13.09μ_B, respectively. HoRh₂Si₂, TbRh₂Si₂ an TbIr₂Si₂ are simple collinear antiferromagnets of +-+- type with Néel temperatures of (27±1), (98±2) and (72±3) K, respectively. For TbRh₂Si₂ and TbIr₂Si₂ magnetic moments are localized on RE ions only and are aligned along the tetragonal axis, while for HoRh₂Si₂ they form an angle ø = (28±3)°.     

13C-selective IRMPD of CBr2F2/Cl2 and CCl2F2/Br2 systems

The CO₂ TEA laser irradiation of CBr₂F₂ in the presence of Cl₂ yielded ¹³C-enriched CBrClF₂ and ¹³C-enriched CCl₂F₂ under selected experimental conditions. As the photolysis proceeded, the ¹³C concentration of CBrClF₂ decreased gradually and that of CCl₂F₂ increased up to 90% or higher. These results can be explained by the mechanism involving the secondary ¹³C-selective IRMPD of the primary product CBrClF₂. On the other hand, the carbon-containing product for a CCl₂F₂/Br₂ system was only CBrClF₂; the further IRMPD of which probably regenerated CBrClF₂ in the presence of Br₂. The decomposition probabilities of ¹²C- and ¹³C-containing molecules in both systems were measured as functions of laser line, laser fluence, and reactant pressures.     

μ+SR study of LaNi2As2, URh2Si2 and CeRh2Si2

Muon spin relaxation experiments have been carried out in the paramagnetic and magnetically ordered states of URh₂Si₂ and CeRh₂Si₂. As the magnetic structure of these compounds is well known, these measurements can help to characterise their magnetic properties probed by μSR and to understand the μSR results of the heavy fermion compounds of the same crystallographic family. Our measurements show that the muons occupy two different crystallographic sites. The spectra of URh₂Si₂ and CeRh₂Si₂ in the magnetically ordered states are very different, probably reflecting their different magnetic structures. The spectra obtained on CeRh₂Si₂ are similar to the published spectra of the heavy fermion compound CeCu_2.1 Si₂. Muon spin rotation measurements on LaNi₂As₂ indicate that the muon is diffusing at 150 K.     

Eu2+掺杂CaSi2O2N2荧光粉发光性能

采用固相反应法合成了组成为Ca_1-xEu_xSi₂O₂N₂的Eu²⁺掺杂CaSi₂O₂N₂荧光粉.通过荧光光谱对样品的发光性能进行了研究,发现Eu²⁺掺杂CaSi₂O₂N₂荧光粉发射光谱为宽波段的单峰结构,主要包含绿光和黄光区,发射峰在556~568 nm.从发射光谱的宽带特征来看,CaSi₂O₂N₂:Eu²⁺的发射主要对应着Eu²⁺离子4f⁶5d→4f⁷跃迁.从激发光谱所覆盖的范围还可以看到,样品可以有效的被UV蓝-光激发,这意味着该类荧光粉在白光LED方面有可能得到广泛的应用.另外,样品的发光性能与激发离子的浓度有着很大关系.激发离子浓度增大时,发射光谱会发生明显红移.利用这一性质,可以通过改变Eu²⁺浓度来调节荧光粉的发光范围,从而满足不同场合的需要.同时,Eu²⁺浓度提高,样品发射光谱的强度也会随之增强,在x=0.06时发射强度达到最大值,之后继续增加Eu²⁺浓度,强度不仅没有增加反而降低,即出现浓度猝灭现象.     

Polar optic phonons in Hg2Cl2 and Hg2Br2

Far infrared (30–430 cm^?1) reflectivity measurements of Hg₂Cl₂ and Hg₂Br₂ single crystals have been performed in polarized light. The spectra, which are in agreement with group-theoretical predictions, were analyzed by the oscillator fitting procedure and Kramers-Kronig method. The results are compared with the existing data from other measurements and the large anisotropy of polar modes is briefly discussed. The polarization vectors of all long-wavelength symmetry modes were determined group-theoretically.     

Magnetostriction of SmMn2Ge2 and GdMn2Ge2 intermetallic compounds

Longitudinal and transverse magnetostrictions of polycrystalline samples of intermetallic compounds RMn₂Ge₂ (R=Sm or Gd) are measured in pulsed magnetic fields up to 250 kOe. It is found that linear magnetostrictive strains of about 10^?3 arise in a temperature range in which the magnetic field causes a change in the magnetic state of a manganese magnetic subsystem. The results obtained are described within the model of a two-sublattice ferrimagnet with a negative exchange interaction in the manganese subsystem in terms of a strong dependence of this interaction on interatomic distances.     

Superconductivity in LaPd_2Bi_2 with CaBe_2Ge_2-type structure

正Since the discovery of superconductivity in LaFeAsO_(1-x)F_x,the high-T_c iron-based superconductors have been extensively studied from both experimental and theoretical viewpoints [1-8]. However, the mechanism of the unconventional superconductivity is still to be resolved. To     

X-ray photoemission spectra measurements of CeNi2Sb2 and CeCu2Sb2

X-ray photoemission spectra, resistivity and susceptibility of CeNi₂Sb₂ and CeCu₂Sb₂ were measured and are discussed. The results indicate that these alloys are Kondo systems. For comparison of the valence band properties, the spectra of the isostructural alloys of RT₂X₂-type with R = La, Gd, T = Cu, Ni and X = Sn, Sb were investigated, too.