基于蒙特卡罗模拟的三维氢原子电子云可视化

本文具体讨论了使用蒙特卡罗模拟对氢原子三维“电子云”进行可视化的方法.根据氢原子中电子的波函数,利用Mathematica软件和蒙特卡罗模拟方法,实现了不同能级的氢原子三维电子云的可视化,使人们对氢原子中电子的行为有更加直观的认识.同时本文也给出了基于蒙特卡罗方法的研究一般原子系统,包括有微扰系统的电子云图像的普适算法,可用于量子力学可视化课程资源的进一步开发.

从比耐公式到类氢原子电子的量子化椭圆轨道

从比耐公式出发 ,结合玻尔———索末菲量子化条件 ,对类氢原子电子的量子化椭圆轨道 ,给出了一个简化的推导 ,并在此基础上 ,对轨道的稳定性进行进一步的讨论。

论辐射效应态氢原子电子的概率位移

物质产生辐射,各种元素的电子受不同辐射光子的影响都会产生康普顿效应,尽管效应的强度不同。物质元素的电子受辐射时产生了康普顿效应称为辐射效应,产生辐射效应后电子的状态称为辐射效应态。氢原子结构简单,氢原子符合波尔理论,即氢原子核外电子具有能级轨道,电子吸收或放出能量会发生轨道跃迁;同时氢原子也遵从量子力学,氢原子核外电子有波函数ψ。辐射效应态下,通过分析氢原子中电子分布的不同位置,应用玻恩概率密度理论,可以求出氢原子的电子辐射效应态沿辐射方向的概率位移。

多重散射展开方法应用于电子-氢原子弹性散射角分布的计算

本文将文献[1]中提出的方法应用于电子-氢原子弹性散射角分布的计算。对所得结果作了讨论,并与实验数据作了比较,符合程度比较好。

Photo‐and electro‐catalytic deuteration of feedstock chemicals and pharmaceuticals:A review

Deuterium labeling techniques are widely utilized as efficient tools to study the absorption,distribution,metabolism,and excretion(ADME)of pharmaceuticals.Moreover,deuterium‐labeled drugs are expected to prolong the half‐life of drug metabolism,enhance the efficacy of drugs,close metabolic sites,and decrease side effects.Thus,there is a rising demand for the practical construction of deuterium‐labeled drugs and their intermediates under mild conditions.This paper timely provides an overview of the recent advances in both photo‐and electro‐catalytic mild and selective deuteration of fine chemicals and pharmaceuticals with low‐cost and sustainable deuterium source.Three types of deuteration strategies are discussed according to the deuteration mode,named deuterium atom transfer strategy,deuterium atom abstraction strategy and deuterated water splitting strategy respectively.The application scope and mechanistic insights are discussed comprehensively.Finally,the perspective on the challenges and future development trends for photo‐and electro‐catalytic deuteration strategies are also presented.

A Mechanistic Switch in C-H Bond Activation by Elusive Fe^(V)(O)(TAML)Reaction Intermediate:A Theoretical Study

The divergent behavior of C-H bond oxidations of aliphatic substrates compared to those of aromatic substrates shown in Gupta’s experiment was mechanistically studied herein by means of density functional theory calculations.Our calculations reveal that such difference is caused by different reaction mechanisms between two kinds of substrates(the aliphatic cyclohexane,2,3-dimethylbutane and the aromatic toluene,ethylbenzene and cumene).For the aliphatic substrates,C-H oxidation by the oxidant Fe^(V)(O)(TAML)is a hydrogen atom transfer process;whereas for the aromatic substrates,C-H oxidation is a proton-coupled electron transfer(PCET)process with a proton transfer character on the transition state,that is,a proton-coupled electron transfer process holding a proton transfer-like transition state(PCET(PT)).This difference is caused by the strongπ-πinteractions between the tetra-anionic TAML ring and the phenyl ring of the aromatic substrates,which has a“pull”effect to make the electron transfer from substrates to the Fe=O moiety inefficient.

Analytical Absorption Cross-Section for Photon by a Hydrogen 2s Atom

We calculate the absorption cross-section for photon by a hydrogen 2s atom using the quantum-classical approximation for the total photo cross-section of many electron atoms. With the application of the first-order term of the Baker Hausdorf expansion, the absorption cross-section for the hydrogen 2s atom decreases to a minimum, the Cooper paJr minimum, at low photon energy. Such a minimum is absent in the exact absorption cross-section for photon by a hydrogen 2s atom. We have extended the calculation for the absorption cross-section of the hydrogen 2s atom using the quantum-classical approximation for the total photo cross-section of many electron to include the second-order term of the Baker-Hausdorf expansion and observed a great reduction in the dip associated with the Cooper pair minimum at the zero crossing.

Circular Rydberg States of Atomic Hydrogen in an Arbitrary Magnetic Field

We report a theoretical scheme using a B-spline basis set to improve the poor computational accuracy of circular Rydberg states of hydrogen atoms in the intermediate magnetic field. This scheme can produce high accuracy energy levels and valid for an arbitrary magnetic field. Energy levels of hydrogen are presented for circular Rydberg states with azimuthal quantum numbers ｜m｜ =10-70 as a function of magnetic field strengths ranging from zero to 2.35 × 10^9 T. The variation of spatial distributions of electron probability densities with magnetic field strengths is discussed and competition between Coulomb and magnetic interactions is illustrated.

Preparation and Characterization of Tungsten-substituted Molybdophosphoric Acids and Catalytic Cyclodehydration of 1,4-Butanediol to Tetrahydrofuran

A series of tungsten-substituted molybdophosphoric acids(H3PMo12-nWnO40·xH2O) were synthesized and characterized by inductive coupled plasma atomic emission spectroscopy(ICPAES),thermal gravimetry and differential scanning calorimetry(TG-DSC),Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),and FTIR pyridine adsorption.The as-prepared heteropoly acids have a Keggin type structure.The synthesis of tetrahydrofuran by reactive distillation and cyclodehydration of 1,4-butanediol was studied using the tungsten-substituted molybdophosphoric acids as catalysts.The results of catalytic test indicated that the catalytic activity increased with the increase in the substitution number(n) of tungsten atom in H3PMo12-nWnO40·xH2O and was constant as the substitution number(n) was more than 8.The catalytic activity increased with the increase in the catalyst loading and the selectivity of tetrahydrofuran was nearly 100%.

Photo-Ionization of Hydrogen Atom in a Circularly Polarized Standing Electromagnetic Wave

Applying time-independent non-perturbative formalism to the photo-ionization of hydrogen atom immersed in a strong circularly polarized standing electromagnetic wave, we calculate the shift of energy levels and the distortion of wave functions for the hydrogen atom, the ionization cross section induced by the standing wave, and the angular distribution of photoelectrons and obtain some interesting results.

One Electron Atom in Special Relativity with de Sitter Space-Time Symmetry

The de Sitter invariant Special Relativity （dS-SR） is SR with constant curvature, and a natural extension of usual Einstein SR （E-SR）. In this paper, we solve the dS-SR Dirac equation of Hydrogen by means of the adiabatic approach and the quasi-stationary perturbation calculations of QM. Hydrogen atom is located in the light cone of the Universe. FRW metric and ACDM cosmological model are used to discuss this issue. To the atom, effects of de Sitter space-time geometry described by Beltrami metric are taken into account. The dS-SR Dirac equation turns out to be a time dependent quantum Hamiltonian system. We reveal that： （i） The fundamental physics constants me, h, e variate adiabatically along with cosmologic time in dS-SR QM framework. But the fine-structure constant α≡ - e^2/（hc） keeps to be invariant; （ii） （2s^1/2 - 2p^1/2）-splitting due to dS-SR QM effects： By means of perturbation theory, that splitting △E（z） are calculated analytically, which belongs to O（1/R^2）-physics of dS-SR QM. Numerically, we find that when ｜R｜ = {103 Gly, 104 Gly, 105 Gly}, and z = {1, or 2}, the AE（z） 〉〉 1 （Lamb shift）. This indicates that for these cases the hyperfine structure effects due to QED could be ignored, and the dS-SR fine structure effects are dominant. This effect could be used to determine the universal constant R in dS-SR, and be thought as a new physics beyond E-SR.