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71.
Roaming Dynamics of H+C\begin{document}$_{2}$\end{document} D\begin{document}$_{2}$\end{document} Reaction on Fundamental-Invariant Neural Network Potential Energy Surface
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We performed extensive quasiclassical trajectory calculations for the H+C\begin{document}$_2$\end{document} D\begin{document}$_2$\end{document} \begin{document}$\rightarrow$\end{document} HD+C\begin{document}$_2$\end{document} D/D\begin{document}$_2$\end{document} +C\begin{document}$_2$\end{document} H reaction based on a recently developed, global and accurate potential energy surface by the fundamental-invariant neural network method. The direct abstraction pathway plays a minor role in the overall reactivity, which can be negligible as compared with the roaming pathways. The acetylene-facilitated roaming pathway dominates the reactivity, with very small contributions from the vinylidene-facilitated roaming. Although the roaming pathways proceed via the short-lived or long-lived complex forming process, the computed branching ratio of product HD to D\begin{document}$_2$\end{document} is not far away from 2:1, implying roaming dynamics for this reaction is mainly contributed from the long-lived complex-forming process. The resulting angular distributions for the two product channels are also quite different. These computational results give valuable insights into the significance and isotope effects of roaming dynamics in the biomolecular reactions. 相似文献
72.
We present a hierarchical construction scheme for accurate ab initio potential energy surface generation. The scheme is based on the observation that when molecular configuration changes, the variation in the potential energy difference between different ab initio methods is much smaller than the variation for potential energy itself. This means that it is easier to numerically represent energy difference to achieve a desired accuracy. Because the computational cost for ab initio calculations increases very rapidly with the accuracy, one can gain substantial saving in computational time by constructing a high accurate potential energy surface as a sum of a low accurate surface based on extensive ab initio data points and an energy difference surface for high and low accuracy ab initio methods based on much fewer data points. The new scheme was applied to construct an accurate ground potential energy surface for the FH(2) system using the coupled-cluster method and a very large basis set. The constructed potential energy surface is found to be more accurate on describing the resonance states in the FH(2) and FHD systems than the existing surfaces. 相似文献
73.
Shaifali Mishra Rajesh K. Yadav Satyam Singh Surabhi Chaubey Pooja Singh Chandani Singh Sarvesh Kumar Gupta Shivani Gupta Dhanesh Tiwary Tae Wu Kim 《Photochemistry and photobiology》2023,99(4):1080-1091
Photocatalysis is a defendable manner for production of several organic chemicals, energy and its storage from solar energy. For the evolution of metal free, cost-effective catalyst a 2D composite has been appear as a photocatalyst. Here, we had reported the synthesis of a light harvesting composite as a photocatalyst which was assembled by a poly-condensation mechanism between graphitic carbon nitride and tetrakis(4-nitrophenyl) porphyrin and the resulting composite manifest the excellent light harvesting properties, suitable energy band and low charge recombination. The photocatalyst [(NO2)4TPP@g-C3N4] enables the efficient photocatalytic production of nicotinamide adenine dinucleotide (NADH) from consumed NAD+ also the production of organic chemicals like 4-methoxybenzylimines from 4-methoxybenzylamines. The photocatalytic efficiency of the photocatalyst was estimated by the percentage of NADH regeneration and the percentage yield of organic transformations. It shows the tetrakis(4-nitrophenyl) porphyrin could enhance the charge transfer capacity of graphitic carbon nitride which shows excellent photocatalysis activities and organic transformations. 相似文献
74.
M. Bina F. Casagrande A. Lulli 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,49(2):257-264
We solve the dynamics of an open quantum system where N strongly driven two-level atoms are equally coupled on resonance to a dissipative cavity mode. Analytical results are derived
on decoherence, entanglement, purity, atomic correlations and cavity field mean photon number. We predict decoherencefree
subspaces for the whole system and the N-qubit subsystem, the monitoring of quantum coherence and purity decay by atomic populations measurements, the conditional
generation of atomic multi-partite entangled states and of cavity cat-like states. We show that the dynamics of atoms prepared
in states invariant under permutation of any two components remains restricted within the subspace spanned by the completely
symmetric Dicke states. We discuss examples and applications in the cases N = 3, 4.
An erratum to this article can be found at 相似文献
75.
We report full-dimensional, electronically adiabatic potential energy surfaces (PESs) for the ground state (1A(')) and excited state (2A(')) of OH(3). The PESs are permutationally invariant fits to roughly 23,000 electronic energies (MRCI + Q/aVTZ). Classical trajectory calculations of the postquenching dynamics of OH A (2)Σ(+) are carried out on the 1A(') PES for H(2) and D(2), at previously identified conical intersections (CoIs) [B. C. Hoffman and D. R. Yarkony, J. Chem. Phys. 113, 10091 (2000)]. The initial momenta are sampled fully and partially microcanonically, corresponding to "adiabatic" and "diabatic" models of the dynamics, respectively. Branching ratios of reactive to nonreactive channels from separate C(2v), C(∞v), and C(s) symmetries of CoIs are calculated, as are final rovibrational state distributions of OH and H(2) products. The rovibrational distributions of the OH and D(2) products, the D/H-atom translational energy distribution are calculated and compared to experimental ones. Agreement for these observable quantities is good. The branching between reactive and nonreactive quenching is sensitive to the momenta sampling; very good agreement with experiment is obtained using the diabatic sampling but not with the adiabatic sampling. The vibrational state distributions of H(2)O and HOD (although not measured by experiment) are also presented. 相似文献
76.
The first mild, efficient, solvent‐free Friedel–Crafts acylation of reserpine has been developed, which resulted in the synthesis of 10‐ and 12‐acylated homologues in high overall yields. 相似文献
77.
A Keggin Polyoxometalate Shows Water Oxidation Activity at Neutral pH: POM@ZIF‐8, an Efficient and Robust Electrocatalyst
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Subhabrata Mukhopadhyay Dr. Joyashish Debgupta Chandani Singh Aranya Kar Prof. Samar K. Das 《Angewandte Chemie (International ed. in English)》2018,57(7):1918-1923
Keggin‐type polyoxometalate anions [XM12O40]n? are versatile, as their applications in interdisciplinary areas show. The Keggin anion [CoW12O40]6? turns into an efficient and robust electrocatalyst upon its confinement in the well‐defined void space of ZIF‐8, a metal–organic framework (MOF). [H6CoW12O40]@ZIF‐8 is so stable to water oxidation that it retains its initial activity even after 1000 catalytic cycles. The catalyst has a turnover frequency (TOF) of 10.8 mol O2(mol Co)?1 s?1, one of the highest TOFs for electrocatalytic oxygen evolution at neutral pH. Controlled experiments rule out the chances of formation and participation of CoOx in this electrocatalyic water oxidation. 相似文献
78.
Abstract Linear poly (ethylene glycol) (PEG) is able to complex with neutral molecular Iodine in the solution state and in solid state, to produce I? 3 ions detectable by conventional spectroscopy and by photoacoustic spectroscopy (PAS). This behavior of PEG is another instance of its ability to mimic the complexation features of the macrocyclic polyether 18-crown-6. 相似文献
79.
1 INTRODUCTION The quinone structure is common in numerous natural products that are associated with antitumor, antibacterial, antimalarial, and antifungal activities[1]. A variety of heterocyclic quinones containing dif- ferent heteroatom substituents could exhibit such activities through different actions and sometimes even improve the activities[2~5]. On the other hand, organophosphorus compounds continue to receive widespread attention due to their ubiquity in biological systems[6, 7]… 相似文献
80.
Abdur Rauf Ghias Uddin Haroon Khan Mohammad Arfan Bina S. Siddiqui 《Natural product research》2016,30(4):426-428
The aim of this study was to explore the extract/fractions and compounds of Diospyros lotus against various Gram-positive and Gram-negative bacteria strain. The results showed marked susceptibility of extract and its fractions against test pathogens. Among them, chloroform fraction was most dominant and effective against all tested bacteria. The chloroform fraction was subjected to column chromatography which led to the isolation of lupeol (1), 7-methyljuglone (2), β-sitosterol (3), stigmasterol (4), betulinic acid (5), diospyrin (6) and 8-hydroxyisodiospyrin (7). Among the isolated compounds, betulinic acid (5) showed significant activity against most of the tested pathogen. In conclusion, our study validated the traditional uses of the plant in the treatment of infectious diseases which was also strongly supported by the isolated compound, betulinic acid (5). 相似文献