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利用SHML模型计算了密度为ρ=1g·cm-3、温度为150eV、200eV、250eV、300eV、400eV的Sn等离子体的随光子能量变化的辐射不透明度及Rosseland平均不透明度.分析了不透明度随光子能量变化曲线的吸收峰值(不透明度峰值)与能级跃迁的对应关系.还将Sn的Rosseland平均不透明度与DCA/UTA及STA模型计算结果作了比较,吻合较好.     

Pt等离子体不透明度的理论计算

利用考虑l能级分裂的屏蔽氢离子模型SHML,计算了重核等离子体Pt在密度温度分别为时束缚—束缚、束缚—自由、自由—自由的吸收系数,并由此计算了Pt等离子体随光子能量变化的辐射不透明度.SHML模型计算的辐射不透明度好于SHM模型的计算结果这是肯定无疑的.     

激光冲击波压缩稠密铝辐射不透明度实验研究

基于稠密物质辐射不透明度的理论计算目前有相当大的难度, 而稠密物质高精度不透明度数据又对聚变研究中的理论设计和模拟以及状态诊断等方面非常有用. 在"神光II"激光装置上建立一发次中能同时测量背光谱、 样品自发谱和吸收谱的大谱窗高分辨椭圆弯晶测谱系统, 并利用一维辐射流体力学程序MULTI仿真冲击波碰撞压缩样品的过程.在测量中, 用点投影背光法、激光烧蚀冲击波碰撞压缩产生稠密铝(Al)样品, 激光镱等离子体3d–4f 跃迁辐射为短脉冲背光提供样品吸收谱时空分辨诊断, 在一发次打靶中得到了背光谱、样品自发谱和X射线吸收精细结构谱, 以及稠密Al辐射吸收谱向长波偏移.实验结果给出了诊断能谱区稠密Al相对透射率分布和吸收谱偏移量. 这些工作都有益于丰富不透明度这一基础研究领域和进一步开拓许多重要应用. 关键词： 冲击波压缩等离子体 X射线吸收谱 线移 精细结构     

高温稠密金等离子体辐射不透明度的多极效应

使用平均原子模型研究了电四极及更高阶跃迁对高温稠密金等离子体辐射不透明度的贡献.计算并讨论了在不同温度密度条件下,电四极,电八极,电十六极跃迁对束缚-束缚跃迁的影响.计算了密度为96.405 g/cm3时,不同温度条件下,电四极,电八极跃迁对Rosseland平均不透明度的贡献.考虑了电四极、电八极跃迁后金等离子体不透明度的相对改变最大分别为4.67%和1.5%,并和其它文献的理论结果进行了比较.     

冲击压缩产生的氩等离子体辐射不透明度研究

采用平面冲击压缩方法产生密度和温度都均匀的氩等离子体,根据光谱辐射强度随时间的变化测量了氩等离子体在可见光区几个波长通道的辐射不透明度,等离子体温度在1.4—2.2eV范围,密度在0.0083—0.015gcm³之间.测量值和理论计算结果符合较好,说明平均原子模型可以较好地描述该热力学条件下氩等离子体的光子输运行为.基板表面的光反射率在确定辐射不透明度时是一个重要参数.采用简化的自洽方法求解基板表面的光反射率.结果表明,基板/氩气界面的光反射率R在0.4附近,与Erskine专门实验 关键词： 物态方程 不透明度 氩     

DTA模型计算高温Fe等离子体的辐射不透明度

使用DTA(detailed term accounting)模型计算了温度为20eV、密度为0.01g×cm^-3的Fe等离子体的辐射不透明度.对于处于局域热动平衡(local thermodynamic equilibrium,LTE)下的Fe等离子体,使用Saha方程计算出各价离子的丰度.使用MCHF方法得到了Fe离子的能级以及束缚-束缚跃迁的振子强度,考虑了Doppler展宽和碰撞展宽的谱线展宽机制,谱线线型采用Voigt线型.束缚-自由以及自由-自由吸收截面分别使用DCA及AA模型得到.所得的结果与美国Los Anamos National Laboratory(LANL)使用LEDCOP程序计算的结果进行了对比,两种结果符合很好.     

非理想性参数在0.9～2.1区的氩等离子体物态方程研究

采用平面冲击压缩方法产生密度和温度都均匀的氩等离子体,根据辐射高温计记录和飞片速度的测定,通过阻抗匹配方法确定了氩等离子体的Hugoniot物态方程,等离子体温度在1.5 eV～2.6 eV范围,压力在0.2～0.8 GPa之间.计算表明,Saha-Debye-Hückel模型不适用于描述该密度区域的氩等离子体.本文采用Gryaznov模型的计算结果,测量值和理论计算结果符合较好.     

高密度氩等离子体电子密度的计算

用屏蔽氢离子模型计算了冲击压缩产生的温度T～2.0eV、密度ρ～0.01g/cm3～0.49g/cm3范围内氩等离子体的电子密度,探讨了不同温度、密度范围内的高密度氩等离子体中粒子之间相互作用对电子密度的影响.     

DTA模型计算高温Mg等离子体的辐射不透明度

使用DTA(detailedtermaccounting)模型计算了温度为 5 6eV、密度为 0 .0 1g/cm3 的Mg等离子体的辐射不透明度以及Rosseland和Planck平均不透明度 .对于处于局域热动平衡 (LTE)下的Mg等离子体 ,利用Saha方程计算出各价离子的丰度 .MCHF方法得到Mg各价离子的能级以及束缚 束缚跃迁的振子强度 ,考虑了Doppler展宽和碰撞展宽 ,谱线线型采用Voigt线型 .束缚 自由以及自由 自由吸收截面使用AA模型得到. The spectral resolved opacity of high temperature Mg plasma at a temperature of 56 eV and a density of 0.01 g/cm 3 is calculated by the detailed term accounting (DTA) model. Saha equation is applied to obtain the population distribution of the plasma in local thermodynamic equilibrium. Atom levels and bound-bound absorption oscillator strengths are obtained from a multi-configuration Hartree-Fock (MCHF) calculation that includes Breit-Pauli relativistic correction. After ...     

稠密、冷铝等离子体的辐射不透明度研究

使用细致谱项模型、联合组态相互作用方法和R 矩阵方法计算了处于局域热动平衡条件下的稠密、冷铝等离子体的辐射不透明度 .组态相互作用方法用于获得束缚 束缚吸收截面所需要的偶极跃迁振子强度 ,R矩阵方法用于获得光电离截面 .对于温度在 6— 12eV、密度为 0 .36mg/cm3 的铝等离子体 ,计算得到的吸收系数在波长为 0 .35 1,0 .5 2 7和 1.0 5 4 μm处与实验结果符合较好 ,而温度在 3— 6eV时 ,理论计算比实验结果大. The radiative opacity has been investigated by using detailed term accounting approximation for dense, cold aluminum plasmas under local thermodynamic equilibrium. The configuration interaction scheme has been used to obtain the relevant atomic parameters for bound-bound absorption, such as excitation energies and oscillator strengths. R-matrix method has been used to obtain the photoionization cross sections. For aluminum plasmas of density 0.36 mg/cm 3, temperature of 6-12 eV, the...     

组氨酸和精氨酸的太赫兹光谱研究

采用太赫兹时域光谱(THz-TDS)测试和理论模拟相结合的方法，研究了组氨酸和精氨酸在THz波段的光谱特性.THz-TDS测试的有效光谱范围为0.2—2.8 THz，在该波段得到样品的特征吸收峰分别位于0.88，1.64，2.23 THz(组氨酸)和0.99，1.47，2.60 THz(精氨酸)；运用Gaussian03半经验理论PM3和AM1算法，计算了两种分子在0.1—10.0 THz波段的振动吸收谱，结果表明它们在该波段均具有多个特征吸收，其中在0.2—2.8 THz波段的吸收峰位与实验吸收峰位相互对应并且符合较好；给出了与光谱特征吸收对应的分子振转模型，为认识分子对THz波的响应机制提供了帮助，也为分子鉴别及更宽有效光谱区的实验测试研究提供了科学依据. 关键词： 太赫兹(THz) 半经验理论 THz时域光谱 氨基酸     

“李时珍石”晶格振动光谱计算

“李时珍石”晶格振动光谱计算曾维杨，毛叔其，毛延哲（兰州大学物理系兰州７３００００）ＣａｌｃｕｌａｔｉｏｎｏｆＴｈｅＶｉｂｒａｔｉｏｎａｌＳｐｅｃｔｒｏｓｅｏｐｙｏｆＬｉｓｈｉｚｈｅｎｉｔｅ￥Ｗｅｉｙａｎｇ；Ｚｅｎｇｓｈｕｑｉ；ＭａｏａｎｄＹａｎｚｈ...     

吡啶－碘电子转移复合物的表面增强拉曼光谱（SERS）研究

吡啶－碘电子转移复合物的表面增强拉曼光谱（ＳＥＲＳ）研究马树国，吴国祯（清华大学物理系北京１０００８４）ＴｈｅＳｕｒｆａｃｅＥｎｈａｎｃｅｄＲａｍａｎＳｔｕｄｙｏｆＴｈｅｃｈａｒｇｅＴｒａｎｓｆｅｒＣｏｍｐｌｅｘｏｆＰｙｒｉｄｉｎｅ－Ｉｏｄｉｎｅｏｎ...     

简介生物学领域中的拉曼散射研究

本文叙述了用拉曼光谱进行生物分子和体系研究的优点，并从生物体系的结构、功能和动力学三方面介绍了拉曼光谱研究工作所取得的一些进展。     

二硼酸锂晶体的压致非晶化研究

二硼酸锂晶体的压致非晶化研究李玉栋，扈士芬，蓝国祥（南开大学物理系天津３０００７１）Ｐｒｅｓｓｕｒｅ－ＩｎｄｕｃｅｄＡｍｏｒｐｈｉｓａｔｉｏｎｏｆＬｉｔｈｉｕｍＤｉｂｏｒｉｔｅ￥ＹｕｄｏｎｇＬｉ；ＳｈｉｆｅｎＨｕａｎｄＧｕｏｘｉａｎｇＬａｎ（Ｄｅｐａ...     

Radiative opacity of plasmas studied by detailed term (level) accounting approaches

Detailed term and level accounting (DTA and DLA) schemes have been developed to calculate the spectrally resolved and Rosseland and Planck mean opacities of plasmas in local thermodynamic equilibrium. Various physical effects, such as configuration interaction effect (including core-valence electron correlations effect and relativistic effect), detailed line width effect (including the line saturation effect), etc., on the opacity of plasmas have been investigated in detail. Some of these physical effects are less capable or even impossible to be taken into account by statistical models such as unresolved transition arrays, super-transition-array or average atom models. Our detailed model can obtain accurate opacity of plasmas. Using this model, we have systematically investigated the radiative opacities of low, medium and high-Z plasmas under different conditions of temperature and density. For example, for aluminum plasma, in the X-ray region, we demonstrated the effects of autoionization resonance broadening on the opacity for the first time. Furthermore, the relativistic effects play an important role on the opacity as well. Our results are in good agreement with other theoretical ones although better agreement can be obtained after the effects of autoionization resonance broadening and relativity have been considered. Our results also show that the modelling of the opacity is very complicated, since too many physical effects influence the accuracy of opacity. For medium and high-Z plasmas, however, there are systematic discrepancies unexplained so far between the theoretical and experimental opacities. Here, the theoretical opacities are mainly obtained by statistical models. To clarify the discrepancies, efforts from both sides are needed. From the view-point of theory, however, a DLA method, in which various physical effects can be taken into account, should be useful in resolving the difference. Taking gold plasma as an example, we studied in detail the effects of core-valence electron correlation and line width on the opacity. Our DLA results correctly explained, for the first time, the relative intensity of the two strong absorption peaks located near the photon energy of 70 and 80 eV, which was experimentally observed by Eidmann et al. [Europhys. Lett., 1998, 44: 459].     

A generalized quasi-sum relations for oscillator strengths in transition arrays: theoretical study of the opacity of Ge plasmas

We present a simplified relativistic configuration interaction method (SRCI), by which all the energy levels and oscillator strengths in each transition array can be calculated. There exist generalized quasi-sum relations for the calculated oscillator strengths in the relevant transition arrays by the SRCI and by an unresolved transition array model (UTA). Based on UTA and the detailed configuration accounting (DCA), with a fully relativistic treatment incorporated with the quantum defect theory, the X-ray absorption spectra for any middle- and high-Z plasmas or composite plasmas can be calculated with much less computational efforts. The gross features of calculated spectra by DCA-UTA are in agreement with the relevant experimental measurements, except some detailed structures in some narrow spectral ranges. Such detailed structures can be calculated by SRCI incorporated with DCA-UTA. As an illustrative example, the absorption spectra of Ge plasmas are calculated by DCA-UTA-SRCI and are in agreement with the experimental opacity data. Therefore, the theoretical method (DCA-UTA-SRCI) verified by experimental measurements will not only be a basic tool to provide “precision” opacity data for the inertial confinement fusion research (ICF) and studies in stellar physics but also can be used to analyze the relevant diagnostic measurements for ICF plasmas.     

液晶分子的抗弯刚度与分子间位致排斥势

定义了反映分子刚性的物理量，称为抗弯刚度Ｋ．给出了用具体的化学键结构和键的力常数计算Ｋ的方法．计算得ＰＡＡ，ａｎｉｓａｌｄｅｈｙｄｅ ａｚｉｎｅ和ＢＡ的Ｋ分别为３．１７×１０⁴，２．９３×１０⁴，４．１７×１０⁴ｎｍｋ_BＫ．导出了分子间位致弹性排斥势．提出了处理弹性棒分子体系的统计物理方法．对ＰＡＡ作了具体的数值计算，并讨论了向列序形成的微观机制：吸引势是主要的，但位致排斥势起十分重要的作用． 关键词：     

电子关联对C60激子极化子的影响

本文采用扩展的Ｈｕｂｂａｒｄ模型，在电子－晶格耦合的紧束缚近似下，研究了光激发下的Ｃ₆₀，分子的激子态和极化子态。我们发现，电子关联效应相当敏感地影响到单态和三态激子的束缚能。同时，Ｃ₆₀分子动力学晶格弛豫使激子极化子得以形成。光激发下的Ｃ₆₀分子，在电子相互作用Ｕ～５．０ｅＶ，Ｖ～２．０ｅＶ时，能够定性地解释荧光发射谱。 关键词：