高密度流体He+H2混合物物态方程研究

选择高密度流体He H2混合物作为研究对象，用Ree混合规则和van der Waals单组分流体变分微扰理论加量子力学一级修正模型编制计算程序。作为对计算模型及其程序的检验，首先用已有的α-exp-6优化势参数，计算了T=300K的He H2混合物的等温相平衡线，得到了与实验值和分子动力学(MD)数值模拟一致的结果，然后进一步计算了0～60GPa和50～7000K压力温度范围内的流体He H2混合物(He H2分别为1：1、1：3、3：1摩尔比)的高压物态方程。与Monte-Carlo模拟数据所进行的比较表明，在低温下，量子力学修正对热力学量的计算是重要的。     

H_2+He流体混合物在部分离解区的物态方程

H2+He流体混合物在高温高压下由于氢的离解化学反应形成由H2,H,He三种粒子构成的混合体系,此时粒子间的相互作用较为复杂,离解能也会由于粒子间的这种复杂相互作用而降低.本文利用自洽流体变分理论来研究部分离解区H2+He流体混合物的高温高压物态方程,模型考虑了各种粒子间的相互作用及由温致和压致效应引起的离解能降低的自洽变分修正,并通过自洽流体变分过程对非理想的离解平衡方程求解得到粒子数密度分布,进而对自由能求导获得体系的热力学状态参量.计算结果与已有的冲击波实验数据、蒙特卡罗模拟及其他理论计算进行了比较.     

高温高密度氢(氘)的物态方程——离解效应研究

 高温高压下流体氢将发生离解化学反应,形成具有相互作用的氢分子和氢原子混合体系,此时粒子间的相互作用复杂。利用单组分流体近似的范德瓦尔斯混合模型,将混合物粒子间的相互作用等效为单组分粒子间相互作用,从而简化了对体系的统计热力学处理;并由自由能函数极小化确定化学平衡时各组分含量、体系的内能、压强。研究了温度在10 000 K以下、密度在0.6 g/cm³以下（相应摩尔体积大于3.3 cm³/mol）区间的热致离解和压致离解现象对流体氢（氘）状态方程的影响。所得结果与双组分流体变分理论计算以及第一原理的分子动力学模拟、蒙特卡罗模拟结果以及二级轻气炮实验数据进行了比较,它们之间的一致性表明：用单组分流体近似的范德瓦尔斯混合模型处理氢（氘）分子的离解区域的物态方程是成功的。     

He+2团簇的形成机理与结合能计算

当He+离子与He原子相互作用时, 由于一个电子往返运动于两核之间形成单电子键, 从而使He+与He结合成为具有较强键能的He+2.根据此形成机理, 采用简单的变分波函数, 计算了He+2基态的能量曲线.结果显示,当核间距为1.74 a 0时, 能量有一极小值-0.090 14 a.u.(以He++He能量为零起始计算).从而得到He+ 2离子结合能为0.090 14 a.u., 这与实验结果0.090 96 a.u.符合得相当好, 比有的理论计算值更接近实验结果.     

He在O2气体中的输运系数的量子力学计算

基于物理力学理论，利用量子力学方法的ＩＯＳＡ近似计算了Ｈｅ在Ｏ２气体中的扩散系数和粘滞系数，计算值与实验值符合较好，比经典计算值更接近实验值。     

类氢He+、Li2+离子的电子碰撞强度的R矩阵计算

利用R矩阵方法计算了电子与He+离子碰撞的1s-2s和1s-2p跃迁的碰撞强度,结果表明包括10个靶态的计算可以得到精确的类氢离子的n=1→n=2各能级跃迁的碰撞强度,并首次利用R矩阵方法计算了电子与Li2+离子碰撞的1s-2s和1s-2p跃迁的碰撞强度.     

The Hugoniot equation of state of the fluid He+D2 mixtures

The fluid variational theory and effective one-component model have been used to calculate the Hugoniot equation of state (EOS) of fluid He, D2, and He+D2 mixtures with different He:D2 compositions under high pressures and temperatures. An examination of the confidence of above computation is performed by comparing experiment and calculation, in which the similar calculation procedure used for He+D2 is adopted, of He and D2 each, since no experimental data are available to conduct this kind of comparison. Good agreement in both comparisons is found. This fact may be looked as if an indirect positive verification of calculation procedure used here at least in the pressure and temperature domain covered by the experimental data of He and D2 used for comparison, numerically nearly up to 35 GPa and 105K.     

He+2团簇结构和解析势能函数的从头计算研究

采用从头计算的耦合簇方法CCSD(T)和He原子Dunning's相关调和基函数组对He+2团簇的结构参数、势能曲线进行计算.利用Murrell-Sorbie函数和最小二乘法拟合出了解析势能函数,并以此为基础计算出光谱常数.通过比较发现:分子结构和光谱常数计算结果均与实验值符合良好,优于文献报道的结果.说明本文所得势能函数解析表达式准确反映了分子中原子间相互作用,可用于更广泛的研究.     

氢分子离子H_2~+键长和基态能量的计算与模拟

利用里兹 (Ritz)变分法求解氢分子离子H+ 2 的键长和基态能量E ,并通过计算机来完成理论公式的推导与数值模拟     

H_2~+分子双H核对高次谐波辐射的贡献

理论研究了H_2~+分子双H核对高次谐波辐射的贡献.结果表明:在少周期激光场下,由于激光场的反对称性,负向H核辐射谐波强度高于正向H核.随着激光脉宽增大,激光波形趋于对称,因此导致双H核辐射谐波的反对称结构减小.谐波辐射的时频分析图显示,当激光场为正向时(E(t)0.0),负向H核辐射谐波强度高于正向H核;当激光场反向时(E(t)0.0),正向H核辐射谐波强度高于负向H核.最后,通过分析含时电子波包及H_2~+的缀饰态给出了电子在双H核之间转移的原因.     

A Comparative Study for the Equation of State of Dense Fluid Hydrogen

Recent developments in shock-wave experimental techniques have allowed the 100 GPa range to be probed. Driven by a two-stage gas gun (Livermore, USA) or chemical explosives (Chernogolovka, Russia), the multiple shock-wave technique has been applied to determine the equation of state and the electrical conductivity of dense hydrogen and deuterium fluids. In single shock wave experiments driven by the NOVA laser, the principle Hugoniot curve of deuterium was determined. Interesting effects such as dissociation and the transition to metallic-like conductivities occur under these conditions. The equations of state applied so far to analyze the experimental data are compared and a new semi-empirical equation of state is given.     

Equation of State of Dense Plasma Mixtures: Application to the Sun Center

We present a self‐consistent approach to the modeling of dense plasma mixtures in local thermodynamic equi‐librium. In each electron configuration the nucleus is totally screened by electrons in a Wigner‐Seitz sphere (ion‐sphere model). Bound and free electrons are treated quantum‐mechanically. The assumption that all species should have the same electronic environment leads to the equality of the electronic pressure for all ions of all elements having therefore different cell volumes. The variation of the average atomic radii of the different elements with respect to temperature is investigated, and the procedure is applied to the determination of pressure in the Sun center (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

中微子束缚效应对致密物质状态的影响

用手征强子模型研究在中微子束缚情况下对致密物质状态及其对前中子星结构的影响.结果表明中微子束缚效应提高了致密物质中质子的含量,使致密物质的状态方程变软,并使前中子星的最大质量与半径减小     

An Analytical Calculation of the Equation of State and the Critical Point in a Dense Classical Fluid of Charged Hard Spheres

A theoretical expression for the equation of state is developed which is based on the mass action law, the Carnahan-Starling expression for the hard-sphere contributions and the mean-spherical approximation for the Coulombic interactions. Numerical calculations of the pressure and the critical data show good agreement with other methods (HNC, MC etc.).     

广义Morse流体解析状态方程及对氮的应用

 根据Ross变分微扰理论以及硬球流体Percus-Yevick（PY） 径向分布函数表达式,建立了广义Morse势流体的解析状态方程。与模拟结果的比较一方面证实了广义Morse 势模型的合理性;另一方面表明了解析Ross变分微扰理论的精度相当或略好于非解析的Weeks-Chandler-Anderson （mWCA）理论,而优于复杂的优化超网络链积分方程理论（RHNC）。该解析状态方程被应用于拟合处于环境温度和压强小于1 GPa情形流体氮的实验数据,所得到的势能参数被用于预测高温高密度情形氮流体的压强,预测结果证实,该解析状态方程可以很好地适用于较宽的压强和温度范围。     

致密物质状态方程:中子星与奇异星

中子星结构一直是核物理、粒子物理和天体物理共同关注的热点难题,双中子星并合事件GW170817的发现更是掀起这一研究的高潮。致密物质的状态方程是决定中子星结构的关键输入量,但是到目前为止,高密度的核物质状态方程行为依然很难确定。如今国内外已有许多运行或规划的大型核实验装置和天文观测设备,有望帮助我们很快解开致密物质状态方程的谜团。本文系统地阐述了基于微观多体理论和唯象模型对脉冲星类天体状态方程的研究现状,也讨论了奇异相变和奇异物质。结合理论计算和核物理实验及天文观测数据,致密物质状态方程的研究已取得相当多进展,但是也面临不少挑战,比如从实验和观测数据提取状态方程信息时的模型依赖,中子星各部分模型的不自洽以及各种依赖热密物质复杂动力学性质的实验和观测量。随着LIGO即将再运行而发现更多双中子星甚至中子星-黑洞等并合事件,多信使天文观测可望最终揭开中子星结构之谜。The matter state inside neutron stars (NSs) is an exciting problem in nuclear physics, particle physics and astrophysics. The equation of state (EOS) of NSs plays a crucial role in the present multimessenger astronomy, especially after the event of GW170817. Thanks to accruing studies with advanced telescopes and radioactive beam facilities, the unknown EOS of supranuclear matter could soon be understood. We review the current status of the EOS for pulsar-like compact objects, that have been studied with both microscopic many-body approaches and phenomenological models. The appearance of strange baryonic matter and strange quark matter are also discussed. We compare the theoretical predictions with different data coming from both nuclear physics experiments and astrophysical observations. Despite great progresses obtained in dense nuclear matter properties, there are various challenges ahead, such as the model dependence of the constraints extracted from either experimental or observational data, the lack of a consistent and rigorous many-body treatment of all parts of the star, the dependence of many observables on the turbulent dynamics of relevant hot dense system. As LIGO is about to run again and discover more NS merger events, multimessenger observations are expected to finally unravel the mystery of NS structure.     

Observation of Excited State Species Due to He2 + and HgBr2 Collisions

Abstract

Emission spectra of HgBr (B-X) band system and atomic mercury lines have been observed during collisions involving HgBr₂ and He₂ ⁺ ions at different laboratory kinetic energies. Emission cross sections of the most intense band of the HgBr (B, v′=O ? X, v″=22) transition have been measured at different energies of the projectile ions.     

碰撞反应Ca+C2H5Br和Ca+nC3H7Br产物CaBr的内能态分布

采用准经典轨线方法研究了碰撞反应Ca+C2H5Br和Ca+nC3H7Br产物CaBr的内能态分布,计算了产物分子CaBr的平均振动、转动和平动能量以及总可资用能量.结果表明,当碰撞能为7.54kJ/mol时,产物的能量主要为振动能量;随着碰撞能增加,产物的平动能和转动能增加,而振动能略微减小,最可几振动态向较低振动能级移动;反应物分子内能态分布对产物分子的内能态分布影响很小;反应基团越大,产物的振动能占总可资用能量的比例就越高.碰撞反应Ca+C2H5Br和Ca+nC3H7Br均存在两条竞争的反应路径迁移相碰和直接反应路径.前者产生高振动激发态产物CaBr,后者引起C-Br键断裂.当碰撞能增加时,两种反应均倾向于后者.