采用提拉法生长出了钕掺杂钽酸钆重闪烁单斜激光晶体(Nd3+:Gd Ta O4).分别测试了该晶体a向、b向和c向的吸收光谱(波段为260—2000 nm),对其中Nd3+的实验能级进行了分析指认.确定了Nd3+:Gd Ta O4的102个实验Stark能级,拟合了其自由离子...采用提拉法生长出了钕掺杂钽酸钆重闪烁单斜激光晶体(Nd3+:Gd Ta O4).分别测试了该晶体a向、b向和c向的吸收光谱(波段为260—2000 nm),对其中Nd3+的实验能级进行了分析指认.确定了Nd3+:Gd Ta O4的102个实验Stark能级,拟合了其自由离子参数和晶体场参数,均方根误差(拟合精度)σ为12.66 cm-1.并将拟合得到的Nd3+:Gd Ta O4实验结果与文献中已报道的Nd3+:GdxLu1-xTa O4(x=0.85)的自由离子参数和晶体场参数进行了比较.结果表明,参数化Stark能级的拟合结果与实验光谱符合得较好.展开更多
The experimental monoclinic CF parameter （CFP） sets obtained by Duan et al. （Phys. Rev. B 75 （2007） 195130） for Er3＋ and Nd3＋ ions in YAIO3 were reanalyzed. These CFPs fitted using R-approach, i.e. with the mo...The experimental monoclinic CF parameter （CFP） sets obtained by Duan et al. （Phys. Rev. B 75 （2007） 195130） for Er3＋ and Nd3＋ ions in YAIO3 were reanalyzed. These CFPs fitted using R-approach, i.e. with the monoclinic second-rank CFP set to zero, and additionally with one six-rank CFP fixed to zero, turned out to be non-standard. In order to understand better the low symmetry aspects involved in the fitted CFPs and extract useful structtral information inherent in monoclinic CFPs, an approach comprising four methods was utilized. First, superposition model （SPM） was applied to calculate CFPs in the crystallographic axis system. Second, the principal values for the SPM determined CFPs and the orientation of the principal axis system w.r.t, the crystallographic axis system were obtained using the procedure 3DD for diagonalization of the 2rid-rank CFPs. Third, analysis of higher symmetry approximations, i.e. orthorhombic and tea＇agonal, was carried out using the pseudosymmetry axes method. Fourth, the closeness factors and norm ratios were employed for quantitative comparisons of various CFP sets. Partial results for Er3＋ ions in YAlO3 were presented here, whereas detailed results would be given in a follow-up paper.展开更多
The annealing behavior for EL2 and EL6 groups as dominant deep levels in semi-insulating GaAs was presented using Photo Induced Transient Spectroscopy measurement (PITS). During rapid thermal annealing, a relation was...The annealing behavior for EL2 and EL6 groups as dominant deep levels in semi-insulating GaAs was presented using Photo Induced Transient Spectroscopy measurement (PITS). During rapid thermal annealing, a relation was identified between EL2 group at 0.79 and 0.82 eV and EL6 group at 0.24, 0.27 and 0.82 eV below the conduction band. It is found that they may be close in structure, and belong to the EL2 and EL6 groups, respectively. In rapidly annealed samples, the quantity of all defects in the EL2 group increases, while that in the EL6 group decreases. However, by furnace annealing at 950°C for 5 h, some of the defects in the EL2 group break up, and the quantity of all defects in the EL6 group increases. It is suggested that the EL2 group and EL6 group are related in their microscopy structures. The relation between the two groups and origins was also discussed.展开更多
The lattice sites occupied by samarium ions in KMgF3 were ascertained. The relationship between valent state of samarium ion in hosts and substituted lattice sites was investigated using fluorescent spectra. It is fou...The lattice sites occupied by samarium ions in KMgF3 were ascertained. The relationship between valent state of samarium ion in hosts and substituted lattice sites was investigated using fluorescent spectra. It is found that the valent state of samarium in different cationic lattice sites is different. The internal relation between the valent state of samarium ion and occupied lattice site was discussed.展开更多
In this paper,the energy levels of Yb^（3＋） ions in yttrium aluminum borate（YAB） crystal were calculated from a first-principles approach with an optimized defect structure obtained from the WIEN2 k package and a ...In this paper,the energy levels of Yb^（3＋） ions in yttrium aluminum borate（YAB） crystal were calculated from a first-principles approach with an optimized defect structure obtained from the WIEN2 k package and a traditional fitting method using a more reliable computer package.The calculated results were then compared with those obtained from a re-calculation using the values of parameters given by some previous researchers.Three types of likely mistakes in the previous researcher＇s paper,namely over fitting,incorrect use of irreducible representation,and errors in the calculations for the EPR parameters were clearly identified and effectively rectified in this paper.The electron paramagnetic resonance（EPR） parameters,which included g factors like g（//） and g⊥ and hyperfine structure constants A// and A⊥,were also calculated through the perturbation method and compared with some observed values available in literature.There was reasonable agreement found with the experimental values which lay between the values obtained from the first-principles calculation（g//=4.000 and g⊥=1.391;A//=1032 and A⊥=360 in 10^（-4） cm^（-1） for ^（171）Yb^（3＋）） and those from the fitting approach（g//=3.612 and g⊥=1.702;A//=867 and A⊥=470 in 10^（-4） cm^（-1） for ^（171）Yb^（3＋））.展开更多
文摘采用提拉法生长出了钕掺杂钽酸钆重闪烁单斜激光晶体(Nd3+:Gd Ta O4).分别测试了该晶体a向、b向和c向的吸收光谱(波段为260—2000 nm),对其中Nd3+的实验能级进行了分析指认.确定了Nd3+:Gd Ta O4的102个实验Stark能级,拟合了其自由离子参数和晶体场参数,均方根误差(拟合精度)σ为12.66 cm-1.并将拟合得到的Nd3+:Gd Ta O4实验结果与文献中已报道的Nd3+:GdxLu1-xTa O4(x=0.85)的自由离子参数和晶体场参数进行了比较.结果表明,参数化Stark能级的拟合结果与实验光谱符合得较好.
基金supported by the research grant from the Polish Ministry of Science and Tertiary Education in the years 2006-2009
文摘The experimental monoclinic CF parameter （CFP） sets obtained by Duan et al. （Phys. Rev. B 75 （2007） 195130） for Er3＋ and Nd3＋ ions in YAIO3 were reanalyzed. These CFPs fitted using R-approach, i.e. with the monoclinic second-rank CFP set to zero, and additionally with one six-rank CFP fixed to zero, turned out to be non-standard. In order to understand better the low symmetry aspects involved in the fitted CFPs and extract useful structtral information inherent in monoclinic CFPs, an approach comprising four methods was utilized. First, superposition model （SPM） was applied to calculate CFPs in the crystallographic axis system. Second, the principal values for the SPM determined CFPs and the orientation of the principal axis system w.r.t, the crystallographic axis system were obtained using the procedure 3DD for diagonalization of the 2rid-rank CFPs. Third, analysis of higher symmetry approximations, i.e. orthorhombic and tea＇agonal, was carried out using the pseudosymmetry axes method. Fourth, the closeness factors and norm ratios were employed for quantitative comparisons of various CFP sets. Partial results for Er3＋ ions in YAlO3 were presented here, whereas detailed results would be given in a follow-up paper.
文摘The annealing behavior for EL2 and EL6 groups as dominant deep levels in semi-insulating GaAs was presented using Photo Induced Transient Spectroscopy measurement (PITS). During rapid thermal annealing, a relation was identified between EL2 group at 0.79 and 0.82 eV and EL6 group at 0.24, 0.27 and 0.82 eV below the conduction band. It is found that they may be close in structure, and belong to the EL2 and EL6 groups, respectively. In rapidly annealed samples, the quantity of all defects in the EL2 group increases, while that in the EL6 group decreases. However, by furnace annealing at 950°C for 5 h, some of the defects in the EL2 group break up, and the quantity of all defects in the EL6 group increases. It is suggested that the EL2 group and EL6 group are related in their microscopy structures. The relation between the two groups and origins was also discussed.
基金The project supported by the National Natural Science Foundation of China
文摘The lattice sites occupied by samarium ions in KMgF3 were ascertained. The relationship between valent state of samarium ion in hosts and substituted lattice sites was investigated using fluorescent spectra. It is found that the valent state of samarium in different cationic lattice sites is different. The internal relation between the valent state of samarium ion and occupied lattice site was discussed.
基金supported by the CRD(RG10/2015-2016R)Dean’s Research Grants of FLASS(CRS-1:04119)Ed UHK and National Natural Science Foundation of China(11547146)
文摘In this paper,the energy levels of Yb^（3＋） ions in yttrium aluminum borate（YAB） crystal were calculated from a first-principles approach with an optimized defect structure obtained from the WIEN2 k package and a traditional fitting method using a more reliable computer package.The calculated results were then compared with those obtained from a re-calculation using the values of parameters given by some previous researchers.Three types of likely mistakes in the previous researcher＇s paper,namely over fitting,incorrect use of irreducible representation,and errors in the calculations for the EPR parameters were clearly identified and effectively rectified in this paper.The electron paramagnetic resonance（EPR） parameters,which included g factors like g（//） and g⊥ and hyperfine structure constants A// and A⊥,were also calculated through the perturbation method and compared with some observed values available in literature.There was reasonable agreement found with the experimental values which lay between the values obtained from the first-principles calculation（g//=4.000 and g⊥=1.391;A//=1032 and A⊥=360 in 10^（-4） cm^（-1） for ^（171）Yb^（3＋）） and those from the fitting approach（g//=3.612 and g⊥=1.702;A//=867 and A⊥=470 in 10^（-4） cm^（-1） for ^（171）Yb^（3＋））.
