共查询到19条相似文献,搜索用时 93 毫秒
1.
2.
电场中Rydberg原子的常数标度能谱方法 总被引:2,自引:0,他引:2
标度能谱理论能够简化外场谱及可以经典方法理解原子外场谱而倍受关注。本文报道了用于电场中Rydberg原子常数标度能谱实验研究的装置以及有关的计算机控制、采集及处理系统。该系统对能量E和电场F进行同步控制以保持标度能谱ε=E/F为常数,并成功地得到Rydberg态Sr原子在标度能ε=-3.0时的标度能谱,经过傅里叶变换,获得了电场中Sr原子的电子回归谱。 相似文献
3.
选择激光偏振方向,同步改变激发激光的波长(即原子的激发能量E)和外加电场强度 F,使标度能ε=E/F保持为常数,得到了原子束中Ba Rydberg原子在标度 能ε=-300时M=0激发的常数标度能谱.由实验标度能谱的Fourier变换得到的回 归谱与氢的均匀化近似后的闭合轨道理论计算相比较,发现实验回归谱的峰值位置与理论计 算符合较好,而峰值强度则与理论相差较大,分析认为是由于受到核散射和双电子微扰态的 影响所致.
关键词:
标度能谱
闭合轨道理论 相似文献
4.
利用原子束 -激光束 -电场相互垂直交叉的实验构型 ,通过同步改变激光激发波长和外加电场强度 ,得到了Sr原子在标度能为 - 3.0时的常数标度能谱。通过对实验谱进行傅里叶变换得到的电子回归谱的分析 ,发现在分岔附近回归峰强度增大。均匀化近似闭合轨道理论计算谱与实验回归谱进行了比较 ,发现在低作用量处两者较好符合。 相似文献
5.
采用射频磁控溅射的方法在SrTiO3(001,基片上制备了(La0.7Sr0.3MnO3)m(BiFeO3)n超晶格间隔的La0.7Sr0.3MnO3三明治结构.X射线衍射分析证明(La0.7Sr0.3MnO3)m(BiFeO3)n具有明显的超晶格结构.电流垂直于薄膜表面测得的电阻-温度关系表明.La0.7Sr0.3MnO3)m(BiFeO3)n超晶格薄膜在290 K有金属-绝缘体转变,略低于单层La0.7Sr0.3MnO3薄膜的转变温度.电流在0.01-10 mA范围内,观察到薄膜的峰值电阻随电流增大而减小,峰值变化率远大于单层La0.7Sr0.3MnO3薄膜,且随着超晶格周期厚度的增加而增大.低温下,电流-电压曲线表明其导电机制应主要为空间载子限制,且显示较大的电压偏置,表现出肖特基结的特性. 相似文献
6.
7.
8.
9.
采用AlOOH/Sr(NO3)2/SiO2/Eu复合胶体喷雾工艺制备了D50=3.83μm球形Sr2Al2SiO7:Eu2 梯次结构荧光粉.复合胶体喷雾过程形成雾滴,雾滴中纳米粒子组分在表面张力及毛细管力作用下自组装形成梯次结构干凝胶粉.干凝胶粉经1300 ℃灼烧得到梯次结构Sr2Al2SiO7:Eu2 荧光粉.X射线衍射(XRD)分析及晶格常量计算结果表明,Eu2 离子部分取代Sr2 格位进入Sr2Al2SiO7晶格.Sr2Al2SiO7:Eu2 荧光体激发谱由峰值位于326 nm附近的宽带构成,属于Eu2 的4f→5d跃迁吸收带;发射光谱峰值波长位于约500 nm处,属于Eu2 离子4f65d到4f7跃迁导致的宽带发射. 相似文献
10.
测量了 Bi2 Sr2 Ca Cu2 O8+δ单晶不同温度下的磁化曲线。根据 Bean临界态模型得到了不同温度下的钉扎力密度 FP 对磁场的依赖关系 ,发现在不同温度下的钉扎力密度可以标度在同一条曲线上。标度函数和最大钉扎力所对应的磁场与不可逆场 Hirr的比值都表明 Si2 Sr2 Ca Cu2 O8+δ单晶在磁通玻璃态的钉扎机制主要是正常相面钉扎。 相似文献
11.
Weihua Zhu 《Journal of Physics and Chemistry of Solids》2007,68(9):1762-1769
Detailed ab initio studies on the electronic structure and optical properties of crystalline strontium azide and barium azide have been performed using density functional theory (DFT) within the generalized gradient approximation (GGA). Relaxed crystal structures compare well with experimental data. An analysis of electronic structure, charge transfer, and bond order shows that the two azides are mainly ionic compounds. Our calculated optical properties are found to be in good agreement with available experimental data. The absorption spectra of the two azides show a number of absorption peaks in the fundamental absorption region. The photoconductivity spectra display a broad photocurrent response in the fundamental absorption region. The density of states of the two azides reveal the effects of the metal states on the valence electron of the azide group, and so are correlated with their thermal decomposition. 相似文献
12.
We show that optical spectroscopy of Rydberg states can provide accurate in situ thermometry at room temperature. Transitions from a metastable state to Rydberg states with principal quantum numbers of 25-30 have 200 times larger fractional frequency sensitivities to blackbody radiation than the strontium clock transition. We demonstrate that magic-wavelength lattices exist for both strontium and ytterbium transitions between the metastable and Rydberg states. Frequency measurements of Rydberg transitions with 10(-16) accuracy provide 10 mK resolution and yield a blackbody uncertainty for the clock transition of 10(-18). 相似文献
13.
C.D. Pinheiro E. Longo E.R. Leite F.M. Pontes R. Magnani J.A. Varela P.S. Pizanni T.M. Boschi F. Lanciotti 《Applied Physics A: Materials Science & Processing》2003,77(1):81-85
We discuss the nature of visible photoluminescence at room temperature in amorphous strontium titanate in the light of the
results of a recent experimental and quantum mechanical theoretical study. Our calculation of the electronic structure involves
the use of first-principles molecular calculations to simulate the variation of the electronic structure in the strontium
titanate crystalline phase, which is known to have a direct band gap, and we also make an in-depth examination of amorphous
strontium titanate. The results of our simulations of amorphous strontium titanate indicate that the formation of five-fold
coordination in the amorphous system may introduce delocalized electronic levels in the highest occupied molecular orbital
and the lowest unoccupied molecular orbital. These delocalized electronic levels are ascribed to the formation of a tail in
the absorbance-spectrum curve. Optical absorption measurements experimentally showed the presence of a tail. The results are
interpreted by the nature of these exponential optical edges and tails associated with defects promoted by the disordered
structure of the amorphous material. We associate them with localized states in the band gap.
Received: 15 January 2002 / Accepted: 7 August 2002 / Published online: 4 December 2002
RID="*"
ID="*"Corresponding author. Fax: +55-16/2615-215, E-mail: derl@power.ufscar.br 相似文献
14.
Malaya K. Nayak Rajat K. Chaudhuri 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,37(2):171-176
Relativistic coupled cluster method (CCM) is applied to
compute the low lying excited and ion states of strontium
and ytterbium atom. The resulting excitation and ionization
energies are in excellent
agreement with experimental data and with other correlated
calculations. The nuclear magnetic dipole hyperfine constants (A)
and electric quadrupole hyperfine constants (B)
of excited states are also evaluated and are in accord with
experiment. We further address the basis set dependency of the
computed properties. 相似文献
15.
The vibrational frequencies and corresponding intensities have been calculated ab initio for the center of the Brillouin zone of crystalline magnesium, calcium, strontium, and barium nitrates; magnesium nitrate hexahydrate; and calcium nitrate tetrahydrate. The calculation has been performed within the electron- density functional theory using the PBE exchange-correlation functional in the basis of localized atomic orbitals with the aid of the CRYSTAL14 software. The calculated values and the experimental IR and Raman spectral data on strontium and barium nitrates are shown to be in satisfactory agreement. The frequencies of normal long-wavelength vibrations in the nitrates become red-shifted with an increase in the cation atomic mass. The occurrence of several peaks due to the vibrations of hydrogen atoms in water molecules with different dynamic charges is predicted in the IR spectrum of hexahydrate magnesium in the frequency range above 3430 cm–1. 相似文献
16.
One-dimensional Fibonacci-type quasi-periodically domain-inverted structures have been successfully fabricated in a strontium barium niobate crystal by electric field poling. With a single such structure, type I phase-matched second-harmonic generation (SHG) has been demonstrated at several wavelengths from red to near ultraviolet. The spectral positions of the observed SHG peaks are in good agreement with theoretical predictions. The range of measured conversion efficiencies is 2-10%. 相似文献
17.
采用先还原后络合的方法,利用草酸将V(V)离子还原并形成络合物,使得全钒氧化还原液流电池(钒电池)电解液的四种价态离子在紫外可见光范围内均具有不同的特征吸收峰.基于此建立了钒电池电解液中不同价态钒离子的光度分析方法,实现对钒离子定性、定量测定.不同价态钒离子标准曲线线性相关系数都大于0.999 0,线性范围分别为0.3... 相似文献
18.
19.
复合氧化物SrEu2O4的合成与光谱特性 总被引:1,自引:1,他引:0
以SrCO3和Eu2O3为原料,采用高温固相反应法在空气气氛中合成了一种Eu和Sr的复合氧化物.利用XRD,TG/DTA和荧光光谱等测试手段对该种新物相的组成、结构和发光性质进行了研究.XRD结果显示,该物相的分子式组成为SrEuO4,与BaEu2O4同构.荧光光谱表明,SrEu2O4存在一个双峰结构的Eu3 -O2-电荷迁移带,峰值分别位于257和280 nm;在紫外光激发下,SrEu2O4以5D0→7F2电偶极发射跃迁(618 nm)最强,发出强的红光. 相似文献