Path integral Monte Carlo approach is used to study the coupled quantum dynamics of the electron and nuclei in hydrogen molecule ion. The coupling effects are demonstrated by comparing differences in adiabatic Born--Oppenheimer and non-adiabatic simulations, and inspecting projections of the full three-body dynamics onto adiabatic Born--Oppenheimer approximation.
Coupling of electron and nuclear quantum dynamics is clearly seen. Nuclear pair correlation function is found to broaden by 0.040 a_0 and average bond length is larger by 0.056 a_0. Also, non-adiabatic correction to the binding energy is found. Electronic distribution is affected less, and therefore, we could say that the adiabatic approximation is better for the electron than for the nuclei.
Excited states of the hydrogen molecule in magnetic fields: The singlet Sigma states of the parallel configuration
本文研究了在均匀磁场作用下氢分子平行组态的激发态，磁场强度B=0- 100 a. u.高达七个激发研究gerade以及ungerade自旋单重态的Sigma对称性与高精度。详细讨论了随着场强的增加，以及光谱的整体行为的各个状态的势能曲线的演变。遇到了各种现象，例如激发态的解离通道的变化序列和由此产生的外阱的形成。所得数据在磁白矮星分析中的可能应用
The nonrelativistic energy of low lying rovibrational levels of HT, DT, and \T\ is determined to an absolute accuracy of $10^{-7}-10^{-8}$ cm$^{-1}$ using the variational method with the four-body nonadiabatic James-Coolidge functions. The new results increase the accuracy of the nonrelativistic component of the energy levels by several orders of magnitude. As a consequence, the total transition energies are improved by at least an order of magnitude.
We report on accurate variational calculations of the Born-Oppenheimer potential for excited states of the hydrogen molecule with $Π$, $Δ$, and $Φ$ symmetries. The obtained potential energy curves reach the relative precision of $10^{-9}$ or better along internuclear distances of 0.01 -- 20 au. Calculations rely on recursive evaluation of two-center two-electron molecular integrals with exponential functions in arbitrary precision arithmetics. Our results for most of the states are the first ever reported, and for the previously calculated states constitute an improvement by several orders of …
Quantum phase transition in the Hartree-Fock wave function of the hydrogen molecule
用二维全数值网格计算方法，在较宽的核间距R范围内，得到了氢分子基态的Hartree-Fock方程的精确解.发现R \infty的单电子波函数的空间部分是一致<2.30a.u. At larger distances they become different and as R->的，它们中的每一个都采取对应于单独原子的形式。这种量子相变发生在R=2.30a.u.给出了分子中电子的离域行为和它们在单独原子上的分布之间的自然边界。这种现象也可以被认为是单分子水平上维格纳结晶或莫特跃迁的模拟。
Ion beam therapy is one of the most progressive methods in cancer treatment. Studies of the water radiolysis process show that the most long-living species that occur in the medium of a biological cell under the action of ionizing irradiation are hydrogen peroxide (H$_2$O$_2$) molecules. But the role of H$_2$O$_2$ molecules in the DNA deactivation of cancer cells in ion beam therapy has not been determined yet. In the present paper, the competitive interaction of hydrogen peroxide and water molecules with atomic groups of non-specific DNA recognition sites (phosphate groups PO$_4$) is investig…
Using a hydrogen molecule as a test system we demonstrate how to compute the effective potential according to the formalism of the new density functional theory (DFT), in which the basic variable is the set of spherically averaged densities instead of the total density, used in the traditional DFT. The effective potential together the external potential, nuclear Coulomb potential, can be substituted in the Schrödinger like differential equation to obtain the spherically averaged electron density of the system. In the new method instead of one three-dimensional low symmetry equation one has to …
Rovibrational energy levels of the hydrogen molecule through nonadiabatic perturbation theory
本文从理论上精确地测定了氢分子及其同位素在电子基态的振转能级。我们认为所有显着的修正玻恩-奥本海默近似，在非绝热微扰理论，包括混合nonadiabatic相对论效应。在领先的$α^5\,m$和次领先的$α^6\,m$订单，以及有限的核尺寸效应的量子电动力学修正，也被考虑在内，但在玻恩-奥本海默近似。最终结果的转振能级之间的过渡波长达到$10^{-3}$- $10^{-7}$ cm $^{-1}$的顺序的精度，并提供了简单的使用计算机代码。
Potential energy surfaces of the hydrogen molecular ion H$_2^+$ in the Born-Oppenheimer approximation are computed by means of the Riccati-Padé method (RPM). The convergence properties of the method are analyzed for different states. The equilibrium internuclear distance, as well as the corresponding electronic plus nuclear energy, and the associated separation constants, are computed to 40 digits of accuracy for several bound states. For the ground state the same parameters are computed with more than 100 digits of accuracy. Additional benchmark values of the electronic energy at different in…
Interactions of Hydrogen Molecules with Halogen-Containing Diatomics from Ab Initio Calculations: Spherical-Harmonics Representation and Characterization of the Intermolecular Potentials
Deciphering the "chemical" nature of the exotic isotopes of Hydrogen by the MC-QTAIM analysis: The positively charged Muon and the Muonic Helium as new members of the Periodic Table
Inelastic Tunneling Spectroscopy of Gold-Thiol and Gold-Thiolate Interfaces in Molecular Junctions: The Role of Hydrogen
人们普遍认为，当具有硫醇（S-H）端基的分子桥接一对金电极时，S原子键合到金上，硫醇H原子从分子上脱离。然而，很少有人知道这个过程的细节，它的时间尺度，以及是否有和没有硫醇氢原子的分子可以共存于分子结。在这里，我们从理论上探讨如何非弹性隧穿光谱（IETS）可以揭示这些问题。我们目前的几何形状，低偏压电导和IETS的丙二硫醇和丙二硫醇分子结与金电极的计算。我们表明，IETS可以区分没有，一个或两个硫醇氢原子的分子之间的结。我们发现，在大多数情况下，在Hihath等人的IETS实验中的单分子结[Nano Lett. 8，1673（2008）]没有硫醇H原子，但是具有单个硫醇H原子的分子可能偶尔桥接它们的连接点。我们还考虑了IETS光谱的演变，作为一个黄金STM尖端接近完整的S-H基团在其另一端绑定到第二个电极的分子的末端。我们预测的硫醇H原子的振动模式的频率增加的一个因素\sim 2的尖端和分子之间的间隙变窄。因此，IETS应该能够跟踪尖端朝向分子的硫醇基团的接近，并且在发生硫醇H原子从分子脱离时检测硫醇H原子。
The Van der Waals interaction of the hydrogen molecule - an exact local energy density functional
我们证明了氢分子的范德华相互作用和所有色散相互作用由W”= -{A/R^6}-{B/R^8}-{C/R^10}-.给出，其中R是核间距，都是完全可溶的。常数A=6.4990267...，B=124.3990835 ...而C=1135.2140398... (in Hartree单位）首先由Pauling和Beach（PB）[1]使用线性变分方法近似获得，可以证明通过我们的精确解可以获得任何所需的精度。此外，我们将表明，一个本地能量密度功能可以得到，其变分解决rederived这个问题的精确解。这明确地表明，一个静态的局部密度泛函理论存在于这个系统。最后，我们的评论推广到其他氢系统的方法，也氦。
We check the ab initio GW approximation and Bethe-Salpeter equation (BSE) many-body methodology against the exact solution benchmark of the hydrogen molecule H$_2$ ground state and excitation spectrum, and in comparison with the configuration interaction (CI) and time-dependent Hartree-Fock methods. The comparison is made on all the states we could unambiguously identify from the excitonic wave functions' symmetry. At the equilibrium distance $R = 1.4 \, a_0$, the GW+BSE energy levels are in good agreement with the exact results, with an accuracy of 0.1~0.2 eV. GW+BSE potential-energy curves a…
