Conventional NMR is generally a technique for electronic ground state molecules. In this paper, the effect of electronic excitation on nuclear magnetic shielding is theoretically illustrated by Nuclear Spin Optical Rotation (NSOR) in liquids. The near-resonance effect on the optical chemical shift in NSOR is explored by using the dressed state theory. The results indicate that in the NSOR spectrum of a molecule with nucleus I = 1/2, such effect can induce a new optical chemical shift line with the circular frequency different from that of the ground state. From it the NMR shielding of a molecule in the electronic excited state can be got directly and used to analyze excited molecule structure in liquids. For multi-nuclei molecules, the result applies to each nucleus.

本文用DFT计算方法研究了LiFe x Mn 1-x PO 4 的热力学稳定性和嵌/脱锂电位.结果表明,LiFe x Mn 1-x PO 4 固溶体的自由能比相分离的LiFePO 4 /LiMnPO 4 混合物略高,这两种形式可能在实际LiFe x Mn 1-x PO 4 材料中共存.计算表明,LiFe x Mn 1-x PO 4 固溶体的嵌/脱锂电位随锰/铁比以及过渡金属离子的空间排列而变化,并用计算结果解释了放电曲线的形状.采用固相反应法合成了LiFe x Mn 1-x PO 4 材料并研究了其电化学性质,实验中观察到附加的放电平台,其出现可能与LiFe x Mn 1-x PO 4 固溶体的存在有关.

The thermodynamic stability and lithiated/delithiated potentials of LiFexMn1-xPO4 were studied with density functional theorical calculations. The results show that the formation free energy of the LiFexMn1-xPO4 solid solution is slightly higher than that of the phase-separated mixture of LiFePO4 and LiMnPO4 and the two forms may co-exist in the actual LiFexMn1-xPO4 materials. The calculation manifests that the lithiated/delithiated potentials of LiFexMn1-xPO4 solid solutions vary via the Mn/Fe ratio and the spatial arrangements of the transition metal ions, and the result is used to explain the shape of capacity-voltage curves. Experimentally, we have synthesized the LiFexMn1-xPO4 materials by solid-phase reaction method. The existence of the LiFexMn1-xPO4 solid solution is thought to be responsible for the appearance of additional capacity-voltage plateau observed in the experiment.

A lithium-rich layered oxide with different shell structures was synthesized by a simple wet-chemical surface deposition method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and other techniques were applied to characterize the crystal structure, morphology, and micro-structure of the samples. The surface of the lithium-rich layered oxide can successively produce island-like spinel, ultra-thin spinel, and thick two-phase (spinel and amorphous manganese oxides) separation shell layers with an increase in the coating amount. The formation process of the different shell structures and the effect of the shell structure on the lattice parameters were discussed. The different shell structures play an important role in the electrochemical performance of the lithium-rich oxide. In particular, when the coating amount is 1wt%, the lithium-rich material with a uniform Li4Mn5O12 spinel shell layer exhibits superior electrochemical performance, and can maintain a discharge capacity of 209.9 mA h g(-1) and 166.8 mA h g(-1) at rates of 2C and 5C.

Lithium-rich layered oxides were synthesized via co-precipitation by using different lithium sources (LiOH, Li2CO3 and CH3COOLi). Scanning electron microscope (SEM), Thermo gravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), Inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD) and electrochemical measurements were used to investigate the morphology, reaction process, specific surface area, composition, structure and electrochemical performance of the lithium-rich oxides, respectively. The use of different lithium sources mainly affects the primary particle size and secondary particle morphology of the final product. Using LiOH as the lithium source, the maximum discharge capacity of sample can reach to 272.1mAhg–1 in the voltage range of 2.0–4.6V at room temperature, even after 50 cycles, the retention rate is still reach 91.4%. The electrochemical impedance spectroscopy (EIS) results show that lithium-rich oxides using LiOH as the lithium source have the minimum value of impedance after 50 cycles. Therefore, the choice of appropriate lithium source is an effective way to improve the electrochemical properties of lithium-rich layered oxides.

The IR absorption, visible excited normal Raman, and UV-excited near-resonant Raman (UVRR) spectra of 1,1′-binaphthyl-2,2′-diamine (BINAM) were measured and analyzed. Density functional theory calculations were carried out to investigate its vibrational frequencies, infrared absorption, normal Raman, and near-resonance Raman intensities. The observed Raman and IR bands of BINAM were assigned with respect to the local vibrations of substituted 2-naphthylamine. Several Raman bands of BINAM were found selectively enhanced in the UVRR in comparison with the normal Raman spectrum. Possible excited state geometry distortion was discussed based on the resonance Raman intensity analysis.

A novel olivine structured LiNi0.75Fe0.25PO4/rGO as a highly effective OER catalyst is comparable to the best noble metal-free OER electrocatalysts reported so far.

Nano-sized MnO intimately embedded in a porous carbon matrix has been synthesized by a facile method in which the manganese-salts/glycerol sol was used as the precursor. The glycerol plays roles of the chelating agent, the carbon source and the solvent. The X-ray diffraction (XRD) and Raman results indicate that the carbon layer may have an obvious effect on the microstructure of MnO. The first-principles density functional theory (DFT) calculations further reveal a considerable charge transfer from MnO to the carbon, leading to a decrease of lattice parameters of MnO and the bond length of Mn-O in the MnO/C composite. The modified microstructure could improve electrochemical performance and meanwhile may explain the phenomenon of exceeding the theoretical capacity. The prepared MnO/C nanocomposite as an anode material displays superior Li-battery performance with a large reversible capacity, excellent cyclic performance and good rate capability.

This work reports for the first time LiNi1−xFexPO4@C nanocomposites as highly effective catalysts for electrochemical oxygen evolution reaction (OER).

Recently, the nuclear-spin-induced optical rotation (NSOR) and circular dichroism (NSCD) for liquids were discovered and extensively studied and developed. However, so far, nuclear-spin-induced magnetic circular dichroism in the IR region (IR-NSCD) has not been explored, even though all polyatomic molecules exhibit extensive IR spectra. Herein, IR-NSCD is proposed and discussed theoretically. The results indicate that in favorable conditions the IR-NSCD angle may be much larger than the NSOR angle in the UV/Vis region due to a vibrational resonance effect and can be measurable by using the NSOR experiment scheme. IR-NSCD can automatically combine and give NMR spectra and IRCD spectra of the nuclear spin prepolarized samples in liquids, which, in principle, could be developed to become a unique, novel analytical tool.

The B state excited resonance Raman scattering of tetraoxaporphyrin dication (TOP2+) was theoretically studied with DFT/TDDFT calculations and the sum-over-states approach of polarizability including both the A and B terms contributions. The resonance Raman spectra calculated with PBE1PBE, B3LYP, Cam-B3LYP, and B3LYP-D3 functionals are similar to each other in general, with PBE1PBE and B3LYP being better in reproducing resonance Raman intensities in comparison with the experiment. The calculated relative intensities of the totally symmetric modes are excellently consistent with the experiment. The TDDFT calculations manifested a considerable deformation of the B state along the ν2, ν6, ν7, and ν8 modes, which is responsible for the strong resonance Raman intensities of these modes. The resonance Raman intensities of non-totally symmetric modes were calculated to be weaker than the totally symmetric modes by one or two order of magnitude, which qualitatively agrees with the experiment. However, the resonance Raman intensity of the ν10 mode (CβCβ stretch, B1g symmetry) predicted by TDDFT calculations is unexpectedly small whereas that of the ν11 mode (symmetric CαCm stretch, B1g symmetry) is too large, which is assumed to be caused by the Jahn-Teller instability for the B state of TOP2+.

A recently proposed optical chemical shift in nuclear spin optical rotation (NSOR) is studied by theoretical comparison of NSOR magnitude between chemically non-equivalent or different element nuclei in the same molecule. Theoretical expressions of the ratio R between their NSOR magnitudes are derived by using a known semi-empirical formula of NSOR. Taking methanol, tri-ethyl-phosphite and 2-methyl-benzothiazole as examples, the ratios R are calculated and the results approximately agree with the experiments. Based on those, the important influence factors on R and chemical distinction by NSOR are discussed.

The infrared absorption and Raman scattering spectra were measured for the metallotriphenylcorroles (MTPCs, M=Cu, Co, Ni, Mn). The ground-state structures and vibrational spectra of MTPCs have been calculated with the density functional theory. The observed Raman and IR bands have been assigned based on the calculation results. Due to the symmetry lowering, the vibrational spectra of MTPCs are much more complex than metalloporphyrins, and several skeletal modes are found strongly coupled to the phenyl vibrations. The relationship between the Raman/IR frequencies and the structures of TPC ring is investigated. It is found that the vibrations involving the CαI stretch and CαCm stretch are sensitive to the size of corrole core. In particular, the frequency of v5, which is assigned to CαI stretch in coupling with the CαCm symmetric stretch, increases linearly with the decrease of the corrole core-sizes and may be used as a mark band to evaluate the structural change of the metallocorroles.

In the present study, a hypercrosslinked polymeric adsorbent (ZH-01) was employed to remove sorbic acid.The study focuses on the static equilibrium adsorption behaviours and the adsorption thermodynamics.Freundlich and Langmuir model give perfect fitting to the isotherm data.The adsorbing capacities for sorbic acid on ZH-01 is higher than on Amberlite XAD-4 within the temperature range 288-318 K, which is contributed to microporous structure and the polar groups on the network of ZH-01 resin.The changes of enthalpy, free energy, entropy were indicative of an exothermic, a spontaneous and disorder decreasing process.The data of the kinetics were fit for the first-order equation.The results showed that the hypercrosslinked polymeric adsorbent (ZH-01) was better than the Amberlite XAD-4 for removing the sorbic acid in aqueous solutions.

The geometries of one-electron reduced/oxidized species ([TOP](-)/[VOP](+)) of vanadyl porphyrin (VOP) have been calculated with PBE1PBE method. The results show that for both [VOP](-) and [VOP](+) the ground states are triplet, in which one of the two unpaired electron occupies the d(xy) orbital of the V atom while the other occupies the pi-orbital of porphyrin ring. Thus both [VOP](-) and [VOP]+ (c)an be considered as pi-radicals. The ground state of neutral VOP molecule is doublet with the unpaired electron occupying dxy orbital of V atom. In contract to the C-4v symmetry of neutral VOP molecule, [VOP](-) anion has a "rectangular" distorted C-2v structure due to Jahn-Teller effect. The linear vibronic coupling constants for the Jahn-Teller active modes of [TOP](-) were evaluated and the node patterns of frontier KS orbitals are used to explain the reason why the distortion occurs along specific modes. The ground state [VOP](+) has a porphyrin ring with pronounced bond length alternation due to pseudo-Jahn-Teller effect, causing its symmetry declined from C-4v to C-4. The bond length alternation is well explained with the node patterns of re-constructed frontier KS orbitals.

The nano-structural LiFePO4/C composites with different interfacial structures were investigated. Fe L-edge XAS spectra indicated that the formation of Fe3+ was related to the interfacial properties of the C-LiFePO4. C K-edge and O K-edge XAS spectra show a distinct bonding character between the carbon and LiFePO4 particle in carbon coated LiFePO4/C. Density functional theory (DFT) calculation was used to analysis the bonding character between the carbon and the LiFePO4 particle and to investigate the formation mechanism of Fe3+. The electrochemical properties are characterized by cyclic voltammograms, constant current charge–discharge, and electrochemical impedance spectra. And it was found that sample A with intimate LiFePO4/carbon interface shows better electrochemical performance than sample B with loose LiFePO4/carbon interface and sample C which had not chemical adsorption between carbon and LiFePO4 particles.

The geometries and electronic spectra of a series of N-protonated corroles, including unsubstituted H4Cor+ and meso-triaryl substituted H4TPC+, H4TpFPC+, and H4TdCPC+, were theoretically studied with density functional theory (DFT). The results indicate that all these compounds have two conformers, one with C2 symmetry (denoted as S1) is more stable than the other (denoted as S2, C1 symmetry) by 15.8–18.5 kJ/mol. The corrole macrocycles of these compounds show significant out-of-plane deformation. The enantiomerizations of the chiral S1 conformers were found to be a multi-step process with the S2 conformers as the intermediates. Electronic absorption spectra and electronic circular dichroism (ECD) of these compounds were calculated with time-dependent DFT. In comparison with H4Cor+, the UV-Vis absorptions of meso-triaryl species are significantly red-shifted and their Q bands are enhanced due to the π-π conjugation between the aryl and corrole rings. Several neighboring electronic transitions were calculated with opposite signs in rotatory strengths, suggesting that ECD spectroscopy may be a useful tool in studying the electronic transitions of these compounds.

Based on Buckingham and Pople's theory of magnetic double refraction, a theoretical expression is derived for a new Cotton-Mouton effect φ(C-M)((IB)) in liquid induced by the crossed effect between the high dc magnetic field B(0) and the nuclear magnetic moment m(z)((l)). It contains temperature-independent and -dependent parts. The latter is proportional to the product between anisotropy of polarizability and the nuclear magnetic shielding tensor. For this new effect φ(C-M)((IB)), its order in magnitude for a molecule with large polarizability anisotropy is estimated to be comparable to the nuclear-spin-induced optical Faraday rotation (NSOFR). In the multipass approach, φ(C-M)((IB)) can be eliminated by time-reversal symmetry arguments, but NSOFR is enhanced.

LiFePO4/C particles with different LiFePO4–C interface were prepared and investigated with emphasis on the interface property which has been found to be important for the power performance of LiFePO4. Soft-X-ray-absorption (XAS) spectra collected at O and C K-edge show a distinct bonding character between carbon and LiFePO4 in carbon coated LiFePO4/C. Galvanostatic change-discharge at different rates and electrochemical impedance tests demonstrate that the interface action between LiFePO4 and carbon within LiFePO4/C composites has a crucial effect on its electrochemical performance.

Based on the thought on the antisymmetric polarizability induced by nuclear magnetic moments and theory of the Faraday effect, an analytical theoretical expression is derived for the nuclear-spin-induced optical rotation (NSOR) of diamagnetic saturated molecules in a circular cylinder. That consists of two parts, ϕ(I) and ϕ(B), induced by the intramolecular and intermolecular hyperfine interaction, respectively. By using them and the Verdet constants, NSOR for 1H in water, hexane, cyclohexane and methyl–alcohol in liquid and H2 gas have been calculated. The calculated NSOR for water agrees with the experiment and for three hydrocarbons predicts the same order of magnitude as water. For the samples studied except H2 gas, ϕ(I) and ϕ(B) are comparable in magnitude.