The nonrelativistic energy together with relativistic and quantum electrodynamic corrections for all the molecular hydrogen isotopologues (D$_2$, T$_2$, HD, HT, DT) were evaluated without expansion in the electron-nucleus mass ratio.
The obtained results significantly improve the uncertainty of theoretical predictions, reaching a value below 1 MHz for the total dissociation energy. We observe good agreement with the experimental value for D$_2$ and $3\,σ$ discrepancy for the HD molecule, while no experimental values for the dissociation energy of molecules involving tritium have yet been obtained.
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 present the first report of optical absorption spectroscopy of H$^{36}\!$Cl, a radioactive isotopologue of hydrogen chloride. We used Fourier-transform infrared spectroscopy to determine the line center wavenumbers of the fundamental rovibrational band lines P(10)-R(10) and the first overtone band lines P(1)-R(7) with total uncertainty of less than 0.0018 cm$^{-1}$ (60 MHz) and 0.007 cm$^{-1}$ (0.2 GHz), respectively, at 68 % confidence level. We also performed a rotational analysis on the bands to determine the related molecular constants. We further compared the linewidths and relative in…
We present a simple method for determination of absolute vibrational numbering of isolated near dissociation levels in diatomic molecules, usually observed in cold physics experiments. The method is based on the isotope shift and works even when energies of only two levels from one isotopologue and one level from another isotopologue have been measured. It is demonstrated on data from recently reported precise measurements of binding energies of levels lying close to the dissociation limits in ultracold Yb2, CsYb, RbSr and RbYb molecules. Its predictions agree with these of much more elaborate…
Lifetimes and wave functions of ozone metastable vibrational states near the dissociation limit in full symmetry approach
能量和寿命（宽度）的振动态以上的最低解离极限的$^{16}$ O $_3$使用以前开发的有效的方法，它结合了超球坐标和复杂的吸收势。计算基于最近计算的以光谱精度确定的臭氧的势能面[J. Chem. Phys. { \bf 139}，134307（2013）]。详细讨论了排列对称性对O $_3$的振转动力学和共振态密度的影响。建立了适合于短程和长程部分的振转连续波函数的量子数之间的对应关系。对称性论证表明，由零核自旋玻色子组成的$^{16}$ O $_3$和$^{18}$ O $_3$的允许纯振动（$J=0$）能级不能在基态势能面上离解.计算了臭氧同位素体$^{16}$ O $_3$的束缚态能量和波函数，转动角动量为$J=0$和1，直到离解阈值.对于束缚能级，计算值与实验值吻合较好，振动能的均方根偏差为1~ \cm。转动常数的测定和用于一个简单的识别计算水平的振动模式。
Unusual dissociative adsorption of H2 over stoichiometric MgO thin film supported on molybdenum
采用周期性密度泛函理论方法系统研究了氢分子在Mo（001）表面MgO（001）薄膜上的解离过程.阐明了异裂游离氢分子在邻近表面氧和表面镁上的异常吸附行为。据我所知，这种异裂解离态以前从未在块状MgO（001）或金属支撑的MgO（001）表面上发现过。结果证实，在所有情况下，异裂解离是更有利的均裂解离能量和动力学。Mo负载1 ML ~ 3 ML氧化膜的两个解离态的能量差很大，在1.1 eV ~ 1.5 eV之间，从反应热力学角度看，这在很大程度上抑制了均裂解离。异裂离解的能垒约为0.5eV，远低于均裂离解的能垒。厚膜上的相变反应将是吸热的。通过异裂离解态，显著降低了获得均裂离解结构所需的反应热和能垒，使H2在2 ML氧化膜上更容易发生均裂离解。研究结果为提高非还原性金属氧化物的反应活性提供了一种有效的方法。
Directly imaging structural dynamics involving hydrogen atoms by ultrafast diffraction methods is complicated by their low scattering cross-sections. Here we demonstrate that megaelectronvolt ultrafast electron diffraction is sufficiently sensitive to follow hydrogen dynamics in isolated molecules. In a study of the photodissociation of gas phase ammonia, we simultaneously observe signatures of the nuclear and corresponding electronic structure changes resulting from the dissociation dynamics in the time-dependent diffraction. Both assignments are confirmed by ab initio simulations of the phot…
The ionization energy of ortho-H$_2$ has been determined to be $E^\mathrm{o}_\mathrm{I}(\mathrm{H}_2)/(hc)=124\,357.238\,062(25)$ cm$^{-1}$ from measurements of the GK(1,1)--X(0,1) interval by Doppler-free two-photon spectroscopy using a narrow band 179-nm laser source and the ionization energy of the GK(1,1) state by continuous-wave near-infrared laser spectroscopy. $E^\mathrm{o}_\mathrm{I}$(H$_2$) was used to derive the dissociation energy of H$_2$, $D^{N=1}_{0}$(H$_2$), at $35\,999.582\,894(25)$ cm$^{-1}$ with a precision that is more than one order of magnitude better than all previous res…
The object of this study is the kinetic process of solid-liquid first-order phase transition - melting of carbon dioxide CS-I hydrate with various cavity occupation ratios. The work was done within a framework of study on the local structure of water molecules. These include the time depending change of the short-range order at temperatures close to the melting point and comparison with hexagonal ice structure. Using molecular dynamics method, dependencies of the internal energy of the studied systems on the time of heating were found. Jumps in the internal energy of solids in the range at 275…
Ion-molecule reactions involving HCO$^+$ and N$_2$H$^+$: Isotopologue equilibria from new theoretical calculations and consequences for interstellar isotope fractionation
$Aims$：我们重新访问与新的增强精度的基本同位素交换反应的理论动力学参与的$^{12}$ C/ $^{13}$ C，$^{16}$ O/ $^{18}$ O，和$^{14}$ N/ $^{15}$ N平衡，因为这些反应已经被实验研究非常详细。$Methods$：电子结构方法被用来探索势能面，全维振转计算，计算振转能级的数值精确，和化学网络模型，以估计在星际条件下的丰度比。$Results$：HCO $^+$与CO反应的新的丰度，提供了与以前的理论值，特别是在低温下，显着不同的速率系数，导致新的丰度比相关的碳化学网络。具体而言，我们得到H $^{12}$ C $^{18}$ O $^+$丰度的减少和H $^{13}$ C $^{16}$ O $^+$和D $^{13}$ C $^{16}$ O $^+$丰度的增加。在所有研究的情况下，离子与中性可极化分子的反应通过中间质子结合的复合物进行，该复合物被发现是非常稳定的。对于复合物OCH $^+$. CO，OCH PDMATHAMV. OC，COHOC $^+$，N $_2$. HCO $^+$，N $_2$ H $^+$. OC，和NPDMATHABMW HN $_2^+$，我们还计算了振动频率和离解能。$Conclusions$：线性质子结合复合物具有相当大的偶极矩，这可能有助于它们的检测。
H-abstraction reactions occurring on electron ionization mass spectrometry (EI-MS) are a long-standing and crucial topic in MS research. Yet some critical relevant mechanisms are controversial and ambiguous, and information about the EI-induced H-abstraction reactions of halogenated organic compounds (HOCs) is completely in the dark. This study provides a systematic investigation of H-abstraction reactions of HOCs taking place on EI source using 13C6-hexachlorobenzene (13C6-HCB) and 13C6-hexabromobenzene (13C6-HBB) as exemplary compounds by gas chromatography high resolution mass spectrometry …
Evidence of Photocatalytic Dissociation of Water on TiO2 with Atomic Resolution
TiO 2表面的光催化分解水反应是氢能技术中具有重要意义的基础问题之一，并得到了广泛的研究。然而，存在的第一个反应步骤，直接光解水，已被忽视。在这里，我们提供了明确的实验证据表明，吸附在金红石型TiO 2（110）-1 \times 1表面的水分子可以解离紫外线照射下，使用低温扫描隧道显微镜。结果表明，在光催化作用下，Ti（Ti_（5c））五配位上的一个水分子发生解离，在Ti_（5c）上生成一个羟基，在桥氧排上生成另一个羟基。我们的研究结果揭示了光催化水裂解反应链中缺失的一环，这大大有助于详细了解潜在的机制。
Engineering NV Centers via Hydrogen-Driven Defect Chemistry in CVD Diamonds for Quantum Applications: NVHx Dissociations into NV, Origin of 468nm Center, and Cause of Brown Coloration
We present an accurate theoretical determination of rovibrational energy levels of the hydrogen molecule and its isotopologues in its electronic ground state. We consider all significant corrections to the Born-Oppenheimer approximation, obtained within nonadiabatic perturbation theory, including the mixed nonadiabatic-relativistic effects. Quantum electrodynamic corrections in the leading $α^5\,m$ and the next-to-leading $α^6\,m$ orders, as well as finite nuclear size effect, are also taken into account but within the Born-Oppenheimer approximation only. Final results for the transition wavel…
High-resolution coherent Raman spectroscopic measurements of all three tritium-containing molecular hydrogen isotopologues T$_2$, DT and HT were performed to determine the ground electronic state fundamental Q-branch ($v=0 \rightarrow 1, ΔJ = 0$) transition frequencies at accuracies of $0.0005$ cm$^{-1}$. An over hundred-fold improvement in accuracy over previous experiments allows the comparison with the latest ab initio calculations in the framework of Non-Adiabatic Perturbation Theory including nonrelativisitic, relativisitic and QED contributions. Excellent agreement is found between exper…
Recent studies have found an unusual way of dissociation in formaldehyde. It can be characterized by a hydrogen atom that separates from the molecule, but instead of dissociating immediately it roams around the molecule for a considerable amount of time and extracts another hydrogen atom from the molecule prior to dissociation. This phenomenon has been coined roaming and has since been reported in the dissociation of a number of other molecules. In this paper we investigate roaming in Chesnavich's CH$_4^+$ model. During dissociation the free hydrogen must pass through three phase space bottlen…
The yardstick of new first-principles approaches to key points on reaction paths at metal surfaces is chemical accuracy compared to reliable experiment. By this we mean that such values as the activation barrier are required to within 1 kcal/mol. Quantum Monte Carlo (QMC) is a promising (albeit lengthy) first-principles method for this and we are now beyond the dawn of QMC benchmarks for these systems, since hydrogen dissociation on Cu(111) has been studied with quite adequate accuracy in two improving QMC studies \cite{hog0, kdd2}. Pt and Cu require the use of pseudo-potentials in these calcu…
Van-der-Waals exchange-correlation functionals and their high pressure and warm dense matter applications
Helmholtz-Zentrum Dresden-Rossendorf e.V. (HZDR)（德累斯顿-罗森多夫亥姆霍兹中心）；Michigan State University（密歇根州立大学）；University of Iowa（爱荷华大学）；Center for Advanced Systems Understanding (CASUS)（高级系统理解中心）
The low-energy electron-impact dissociation of molecular hydrogen has been a source of disagreement between various calculations and measurements for decades. Excitation of the ground state of H$_2$ into the dissociative $b ^3Σ_u^+$ state is now well understood, with the most recent measurements being in excellent agreement with the molecular convergent close-coupling (MCCC) calculations of both integral and differential cross sections (2018 Phys. Rev. A 98 062704). However, in the absence of similar measurements for vibrationally-excited or isotopically-substituted H$_2$, cross sections for d…
We report results of a theoretical investigation of hyperfine interactions in two homonuclear isotopologues of the hydrogen molecule: H$_{2}$ and D$_{2}$. We present a set of hyperfine coupling constants: spin-rotation, spin-spin dipole and, in the case of the D$_{2}$ molecule, electric quadrupole coupling constants for all bound states of the two isotopologues in their ground electronic $X^{1}Σ^{+}_{g}$ state. We provide a list of positions and intensities of 220 997 hyperfine components of 16 079 rovibrational quadrupole transitions of the O, Q and S branches. The positions and intensities o…
