中高能正电子被CO，HCl，NH3及SiH4散射的总截面

利用可加性规则，使用Hartree-Fock波函数，采用由束缚原子概念修正过的复光学势(由静电势、极化势及吸收势三部分组成)，在30—3000eV内对正电子被CO，HCl，NH₃和SiH₄散射的总截面进行了计算，且将计算结果与实验结果及其他理论计算结果进行了比较.结果表明，利用被束缚原子概念修正过的复光学势及可加性规则进行计算，所得结果与实验结果的符合程度要比利用未被束缚原子概念修正的复光学势及可加性规则进行计算得到的结果好很多.因此，在复光学势中采用束缚原子概念可提高正电子被分子散射的总截面的计算准确度. 关键词： 正电子散射 可加性规则 束缚原子 总截面     

中高能电子被甲烷及氯代甲烷散射的总截面

利用可加性规则，使用HartreeFock波函数，采用由束缚原子概念修正过的复光学势（由静 电势、交换势、修正极化势及吸收势这四部分组成），在较大的能量(30—5000eV)范围内对 电子被甲烷及氯代甲烷（CH₄，CCl₄，CHCl₃，CH₂Cl₂和CH ₃Cl）散射的总截面进行了计算，且将计算结果与实验结果及其他理论计算 结果进行 了比较.结果表明，利用被束缚原子概念修正过的复光学势及可加性规则进行计算，所得结 果的精度要比利用未被束缚原子概念修正的复光学势及可加性规则进行计算得到的结果好很 多.因此，在复光学势中采用束缚原子概念可提高电子被分子散射的总截面的计算准确度. 关键词： 电子散射 可加性规则 束缚原子 总截面     

100～5 000 eV下电子被等电子(Z=10)分子CH4、H2O、HF及NH3散射的总截面计算

利用可加性规则,使用Roothaan-Hartree-Fock波函数,在100～5 000 eV下首次采用由束缚原子概念修正过的复光学势,对电子被等电子(Z=10)分子CH4、H2O、HF和NH3散射的总截面进行了计算.束缚原子不同于自由原子之处,是束缚原子考虑了在不同分子中电子云的不同重叠,将计算结果与实验及其它计算结果进行了比较.结果表明,利用被束缚原子概念修正过的复光学势及可加性规则进行计算,其结果的精度要比利用未被束缚原子概念修正过的复光学势及可加性规则进行计算得到的结果好.     

中高能电子被O2及CF4分子散射的微分截面、弹性积分截面及动量转移截面

利用可加性规则,使用Roothaan-Hartree-Fock波函数,采用由束缚原子概念修正过的复光学势,在300-1000 eV内若干个能量点处计算了电子被O2及CF4分子散射的微分截面、弹性积分截面及动量转移截面,并将计算结果与实验结果及其他理论计算结果进行了比较.比较的结果表明,利用被束缚原子概念修正过的复光学势及可加性规则进行计算,所得微分散射截面的精度要比利用未修正的复光学势及可加性规则进行计算得到的结果准确得多;同时,计算得到的弹性积分截面及动量转移截面也比较接近实验值.因此,在复光学势中采用束缚原子概念可提高电子被分子散射的微分截面、弹性积分截面及动量转移截面的计算准确度.     

中高能电子被O2及CF4分子散射的微分截面、弹性积分截面及动量转移截面

利用可加性规则，使用Roothaan-Hartree-Fock波函数，采用由束缚原子概念修正过的复光 学势，在300—1000eV内若干个能量点处计算了电子被O₂及CF₄分子 散射的微分截面、 弹性积分截面及动量转移截面，并将计算结果与实验结果及其他理论计算结果进行了比较. 比较的结果表明，利用被束缚原子概念修正过的复光学势及可加性规则进行计算，所得微分 散射截面的精度要比利用未修正的复光学势及可加性规则进行计算得到的结果准确得多；同 时，计算得到的弹性积分截面及动量转移截面也比较接近实验值.因此，在复光学势中采用 束缚原子概念可提高电子被分子散射的微分截面、弹性积分截面及动量转移截面的计算准确 度. 关键词： 电子散射 可加性规则 微分截面 弹性积分截面     

30-3000eV的正电子被O2、H2O及CH4散射的总截面计算

使用可加性规则，在Hartree-Fock水平上计算了30-3000eV的正电子被三个分子（O2、H2O及CH4）散射的总截面。计算正电子被三个分子散射的总截面时，首次使用了被束缚原子概念修正过的复光学势（这一复光学势考虑了分子中两个原子间的电子云重叠效应）。将正电子被这三个分子散射的总截面计算结果与实验结果及其它理论计算结果进行了比较，结果显示出在30-3000eV内，文中的计算结果与实验结果及其它理论计算结果具有较好的一致性。因此，可加性规则与修正后的复光学势相结合，完全适用于正电子被分子散射的总截面的计算。     

30-5000eV的电子被若干分子散射的总截面计算的一种修正势方法

利用可加性规则，使用Hartree-Fock波函数，采用由束缚原子概念修正过的复光学势，在30~5000eV这一较大的能域内对电子被N2、NO、NO2、CH4、CF4、CF3H、C2H2及C2H4散射的总截面进行了计算。束缚原子不同于自由原子之处，是束缚原子概念考虑了不同分子中的不同的电子云重叠情况，并根据电子云的重叠情况对复光学势进行修正。文中，将定量的计算结果与实验结果及其它理论计算结果进行了比较，结果显示出在30~5000eV内，计算结果与实验结果及其它理论计算结果间有较好的一致性。同时结果也表明，在较低的能量下，尤其是当入射电子的能量低于500eV时，利用被束缚原子概念修正过的复光学势进行计算得到的结果，要比利用未被束缚原子概念修正的复光学势计算得到的结果更接近于实验值。因此，在复光学势中考虑电子云的重叠效应可改善电子被分子散射的总截面的计算精度。     

中高能电子被氟代甲烷散射的总截面计算

利用可加性规则,使用Hartree-Fock 波函数,采用被束缚原子概念修正过的复光学势,首次在100～5 000eV内对电子被具有较多电子数的氟代甲烷分子散射的总截面进行了计算,且将计算值与实验值及经验公式进行了比较,得出了被束缚原子概念修正过的复光学势可成功用于"电子-氟代甲烷"散射总截面计算的结论;研究了"电子-氟代甲烷"的散射总截面与目标分子总电子数及电子入射能量间的关系,初步分析了结构因子与总电荷数相关的原因,并指出了对复光学势进行进一步修正时应遵循的原则.     

一种计算中、高能电子被分子散射总截面的修正势方法

在考虑分子内成键原子间的电子云重叠效应的基础上，提出了一种能够在中、高能区准确计算“电子-分子”散射总截面的修正势方法.利用可加性规则及Hartree-Fock波函数，使用这一修正过的复光学势，在30—5000eV内对电子被4个等电子(Z=18)分子(HCl，H₂S，PH₃和SiH₄)散射的总截面进行了计算，并将理论计算值与实验结果及其他理论值进行了比较.结果表明，利用这一修正过的复光学势及可加性规则进行计算，所得理论值与实验结果更为接近. 关键词： 电子散射 总截面 可加性规则 束缚原子     

中、高能电子被SO2分子散射的微分截面、动量转移截面及弹性积分截面

在考虑分子内成键原子间的电子云重叠效应的基础上, 提出了一种能够准确计算“中、高能电子-分子”散射的微分截面、动量转移截面及弹性积分截面的修正势方法. 利用可加性规则、使用Hartree-Fock波函数并采用被这一方法修正过的复光学势, 在100—1000eV内对电子被SO₂分子散射的微分截面、动量转移截面及弹性积分截面进行了计算, 并将计算结果与实验及其他理论结果进行比较. 结果表明, 利用这一修正过的复光学势及可加性规则获得的微分截面比利用未修正的复光学势及可加性规则得到的结果准 关键词： 可加性规则 微分截面 动量转移截面 电子散射     

Solution absorption and luminescence studies of tetraphenylboron, -carbon, -silicon, -germanium, -tin, -lead, -phosphorus, -arsenic,and -antimony

The lowest absorption band of the tetraphenyl compounds resembles that of the lowest absorption band of benzene with the following difference. In benzene the electronic origin is strictly forbidden, and all intensity is associated with a symmetric progression built on one mode of asymmetric vibration. In the tetraphenyl compounds the intensity associated with the asymmetric vibration is relatively unaffected; however, there is increasing intensity associated with the electronic origin and a symmetric progression built on it along the series

$\text{φ}{}_4\text{Pb}\text{< φ}{}_4\text{Sn}\text{< φ}{}_4\text{Ge}\text{< φ}{}_4\text{Si}\text{< φ}{}_4\text{C}\text{? φ}{}_4\text{B}{}^{\mathrm{?}}\text{< φ}{}_4\text{Sb}{}^{\mathrm{+}}\text{< φ}{}_4\text{As}{}^{\mathrm{+}}\text{< φ}{}_4\text{P}{}^{\mathrm{+}}$

. For the cations it is the electronic origin and the progression built on it that are the primary source of intensity. This effect is attributed to an inductive perturbation. A similar effect is observed in the fluorescence spectrum. In phosphorescence, the relative enhancement of the electronic origin and the progression built on it is far less marked. The phosphorescence emission of φ₄Pb and φ₄Sb⁺ are red shifted from the others by ～0.5 eV, an effect attributed to formation of a triplet excimer. Increasing spin-orbit coupling in the triplet due to a heavy atom effect can be seen in the decreasing phosphorescence lifetime (range 4 sec to 4 msec) and decreasing ratio of $\text{φ}{}_{\mathrm{f}}\text{φ}{}_{\mathrm{p}}$ (fluorescence to phosphorescence quantum yields) in the order

$\text{φ}{}_4\text{C}\text{> φ}{}_4\text{B}\text{> φ}{}_4\text{Si}\text{> φ}{}_4\text{P}{}^{\mathrm{+}}\text{> φ}{}_4\text{Ge}\text{> φ}{}_4\text{As}{}^{\mathrm{+}}\text{> φ}{}_4\text{Sn}$

In all cases nonexponential decay of phosphorescence is observed.     

Quarks,diquarks, tetraquarks,and pentaquarks

A particle about 50% more massive than a proton, with positive charge, positive strangeness and positive baryon number, has been claimed in several experiments. Such a particle cannot be made from three quarks; its minimal configuration requires four quarks and an antiquark and it became known as a ‘pentaquark’. This article summarizes the evidence and concentrates on the theoretical interest that it has excited into the nature of correlations among quarks and antiquarks in the strong interaction limit of QCD.     

Bits,time, carriers,and matter

The formal structure of quantum information theory is based on the well-founded concepts and postulates of quantum mechanics. In the present contribution, I am inverting the usual approach presented in textbooks by beginning with the use of bit states as basic and fundamental units of information and establish a dynamical map for them. The condition of reversibility, imposed on an ordered sequence of actions operating on a bit state, introduces, by necessity, the unitarity property of actions. I also verify that the uniformity of time, as a parameter for ordering events, is due to the admission of a composition law for the actions. In the limit of infinitesimal intervals between actions, a reversible and linear equation arises for the dynamical changes in time of a qubit (superposition of bit states). The admission that a bit of information is stored or carried by a massive particle necessarily leads to the Schrödinger–Pauli equation (SPE); the bit is associated to a spin 1/2. Within this approach, I verify that the particle dynamical equation becomes “enslaved” by the spin dynamics. In other words, the bit (or spin) precedes in status the particle dynamical evolution, being at the root of the quantum character of the standard Schr¨odinger equation, even when spin and spatial degrees of freedom are uncoupled.     

Walks,walls, wetting,and melting

New results concerning the statistics of, in particular,p random walkers on a line whose paths do not cross are reported, extended, and interpreted. A general mechanism yielding phase transitions in one-dimensional or linear systems is recalled and applied to various wetting and melting phenomena in (d=2)-dimensional systems, including fluid films and p×1 commensurate adsorbed phases, in which interfaces and domain walls can be modelled by noncrossing walks. The heuristic concept of an effective force between a walk and a rigid wall, and hence between interfaces and walls and between interfaces, is expounded and applied to wetting in an external field, to the behavior of the two-point correlations of a two-dimensional Ising model belowT _c and in a field, and to the character of commensurate-incommensurate transitions ford=2 (recapturing recent results by various workers). Applications of random walk ideas to three-dimensional problems are illustrated in connection with melting in a lipid membrane model.Based on the Boltzmann Medalist address presented at the 15th IUPAP International Conference on Thermodynamics and Statistical Mechanics, Edinburgh, July 1983.     

Einstein,Podolsky, Rosen,and Shannon

The Einstein–Podolsky–Rosen paradox (1935) is reexamined in the light of Shannons information theory (1984). The EPR argument did not take into account that the observers information was localized, like any other physical object.Dedicated to the memory of James T. Cushing     

Black swans,power laws,and dragon-kings: Earthquakes,volcanic eruptions,landslides, wildfires,floods, and SOC models

Extreme events that change global society have been characterized as black swans. The frequency-size distributions of many natural phenomena are often well approximated by power-law (fractal) distributions. An important question is whether the probability of extreme events can be estimated by extrapolating the power-law distributions. Events that exceed these extrapolations have been characterized as dragon-kings. In this paper we consider extreme events for earthquakes, volcanic eruptions, wildfires, landslides and floods. We also consider the extreme event behavior of three models that exhibit self-organized criticality (SOC): the slider-block, forest-fire, and sand-pile models. Since extrapolations using power-laws are widely used in probabilistic hazard assessment, the occurrence of dragon-king events have important practical implications.