The highly exothermic hydrogen abstraction reaction H2Te + OH → H2O + TeH: comparison with analogous reactions for H2Se and H2S.

The "gold standard" CCSD(T) method is adopted along with the correlation consistent basis sets up to aug-cc-pV5Z-PP to study the mechanism of the hydrogen abstraction reaction H2Te + OH. The predicted geometries and vibrational frequencies for reactants and products are in good agreement with the available experimental results. With the ZPVE corrections, the transition state in the favorable pathway of this reaction energetically lies 1.2 kcal mol-1 below the reactants, which is lower than the analogous relative energies for the H2Se + OH reaction (-0.7 kcal mol-1), the H2S + OH reaction (+0.8 kcal mol-1) and the H2O + OH reaction (+9.0 kcal mol-1). Accordingly, the exothermic reaction energies for these related reactions are predicted to be 47.8 (H2Te), 37.7 (H2Se), 27.1 (H2S), and 0.0 (H2O) kcal mol-1, respectively. Geometrically, the low-lying reactant complexes for H2Te + OH and H2Se + OH are two-center three-electron hemibonded structures, whereas those for H2S + OH and H2O + OH are hydrogen-bonded. With ZPVE and spin-orbit coupling corrections, the relative energies for the reactant complex, transition state, product complex, and the products for the H2Te + OH reaction are estimated to be -13.1, -1.0, -52.0, and -52.6 kcal mol-1, respectively. Finally, twenty-eight DFT functionals have been tested systematically to assess their ability in describing the potential energy surface of the H2Te + OH reaction. The best of these functionals for the corresponding energtics are -9.9, -1.4, -46.4, and -45.4 kcal mol-1 (MPWB1K), or -13.1, -2.4, -57.1, and -54.6 kcal mol-1 (M06-2X), respectively.

Stationary Points on Potential Energy Surface of Cyclic C3H3 with Coupled-Cluster Approaches and Density Functional Theory.

Cyclic C3H3 is the simplest cyclic hydrocarbon, but its configuration is complicated. The ground 2E″ state at the equilateral triangle geometry with D3h symmetry undergoes both Jahn-Teller (JT) distortion and pseudo-Jahn-Teller (PJT) distortion to structures with C3v, C2v, Cs, or C2 symmetry. Previous works using complete active space self-consistent field (CASSCF) or multiconfiguration SCF (MCSCF) differ on the characteristics of these structures. To clarify the characteristics of these stationary points on the potential energy surface (PES) of this radical, coupled-cluster methods CCSD, CCSD(T), and EOMEA/IP-CCSD as well as density functional theory are employed to calculate their geometries, harmonic frequencies, and relative energies. Deformations between these stationary points due to JT and PJT effects are analyzed in detail. Most of the results with these methods are consistent with each other, except for the b2 mode of the 2B1 state with C2v symmetry. CCSD and CCSD(T) provide an imaginary frequency for this vibrational mode, while it is calculated to be real with the other methods as well as with EOM-CCSDT-3. This may be related to unstable reference in CCSD and CCSD(T) calculations. On the other hand, most of the employed exchange-correlation functionals provide reliable results on the characteristics of these stationary points. Our results show that the 2A' state with Cs symmetry is the only minimum structure on the PES of cyclic C3H3. The 2A2 and 2B1 states of the C2v structure are second-order saddle points, while both the 2A state of the C2 structure and the 2A″ state of the Cs structure are transition states connecting the global minimum 2A' state.

Correction: Single-precision open-shell CCSD and CCSD(T) calculations on graphics processing units.

Correction for 'Single-precision open-shell CCSD and CCSD(T) calculations on graphics processing units' by Zhifan Wang et al., Phys. Chem. Chem. Phys., 2020, 22, 25103-25111, DOI: .

Single-precision open-shell CCSD and CCSD(T) calculations on graphics processing units.

It has been shown that coupled-cluster calculations with single-precision data are able to provide correlation energy with insignificant loss of accuracy. In this work, we employed consumer GPUs to accelerate open-shell spin-unrestricted CCSD and CCSD(T) calculations based on single-precision data. Some open-shell molecules are calculated to benchmark the acceleration performance of GPUs. In CCSD calculations, good acceleration performance on consumer GPUs is achieved for molecules when all the two-electron integrals can be saved in the host memory. On the other hand, I/O operations cost a lot of time for larger molecules and the performance of GPUs is not as significant. Good acceleration performance can usually be obtained in calculating the (T) correction employing GPUs since matrix contractions are always more costly than other operations. For systems with less than four hundred basis functions, our single-precision GPU code could provide an acceleration of 4-14 times for CCSD calculations and 12-20 times for (T) correction compared with double-precision CPU codes on the same hardware level.

Low-lying states of MX2 (M = Ag, Au; X = Cl, Br and I) with coupled-cluster approaches: effect of the basis set, high level correlation and spin-orbit coupling.

Theoretical study of coinage metal dihalides is challenging due to their complex electron correlation and relativistic effects, particularly the spin-orbit coupling (SOC) effect. Furthermore, vibrational frequencies and characters of their low-lying states are affected by the Renner-Teller effect (RTE) and pseudo-Jahn-Teller effect (PJTE). The theoretical results depend on the basis set and how the electron correlation is treated and previous results even differ qualitatively in the ground state for some silver dihalides. The equation-of-motion coupled-cluster method at the singles and doubles level (EOM-CCSD) for ionization potentials is employed in this work to calculate electron affinities and vertical excitation energies of MX2 (M = Ag, Au; X = Cl, Br and I) as well as structures, harmonic frequencies and adiabatic excitation energies for the lowest two states of these molecules. Effects of the higher level correlation, basis set as well as SOC on these results, particularly on the πu bending mode frequencies of the 2Πg state, are investigated. A new assignment for photodetachment spectroscopy of AuCl2- is proposed where contribution of the 2Δg state is considered. The ground state of AgCl2 is calculated to be the 2B2 state of the C2v structure in scalar-relativistic (SR) calculations, while the SOC quenches the RTE and PJTE and the ground state becomes the 2Π3/2g state of the D∞h structure. As for the other molecules, the ground state is calculated to be the 2Πg state in SR cases, and the 2Π3/2g state with SOC. Our results indicate that a higher level electron correlation, large basis set and SOC are important to achieve reliable results for these molecules.

Equation-of-motion coupled-cluster theory for double electron attachment with spin-orbit coupling.

We report implementation of the equation-of-motion coupled-cluster (EOM-CC) method for double electron-attachment (DEA) with spin-orbit coupling (SOC) at the CC singles and doubles (CCSD) level using a closed-shell reference in this work. The DEA operator employed in this work contains two-particle and three-particle one-hole excitations, and SOC is included in post-Hartree-Fock treatment. Time-reversal symmetry and spatial symmetry are exploited to reduce computational cost. The EOM-DEA-CCSD method with SOC allows us to investigate SOC effects of systems with two-unpaired electrons. According to our results on atoms, double ionization potentials (DIPs), excitation energies (EEs), and SO splittings of low-lying states are calculated reliably using the EOM-DEA-CCSD method with SOC. Its accuracy is usually higher than that of EOM-CCSD for EEs or DIPs if the same target can be reached from single excitations by choosing a proper closed-shell reference. However, performance of the EOM-DEA-CCSD method with SOC on molecules is not as good as that for atoms. Bond lengths for the ground and the several lowest excited states of GaH, InH, and TlH are underestimated pronouncedly, although reasonable EEs are obtained, and splittings of the 3Σ- state from the π2 configuration are calculated to be too small with EOM-DEA-CCSD.

Splittings of d8 configurations of late-transition metals with EOM-DIP-CCSD and FSCCSD methods.

Multireference methods are usually required for transition metal systems due to the partially filled d electrons. In this work, the single-reference equation-of-motion coupled-cluster method at the singles and doubles level for double ionization potentials (EOM-DIP-CCSD) is employed to calculate energies of states from the d8 configuration of late-transition metal atoms starting from a closed-shell reference. Its results are compared with those from the multireference Fock-space coupled-cluster method at the CCSD level (FSCCSD) for DIP from the same closed-shell reference. Both scalar-relativistic effects and spin-orbit coupling are considered in these calculations. Compared with all-electron FSCCSD results with four-component Dirac-Coulomb Hamiltonian, FSCCSD with relativistic effective core potentials can provide reasonable results, except for atoms with unstable reference. Excitation energies for states in the (n - 1)d8ns2 configuration are overestimated pronouncedly with these two methods, and this overestimation is more severe than those in the (n - 1)d9ns1 configuration. Error of EOM-CCSD on these excitation energies is generally larger than that of FSCCSD. On the other hand, relative energies of most of the states in the d8 configuration with respect to the lowest state in the same configuration are predicted reliably with EOM-DIP-CCSD, except for the 3P0 state of Hg2+ and states in Ir+. FSCCSD can provide reasonable relative energies for the several lowest states, while its error tends to be larger for higher states.

Approximate equation-of-motion coupled-cluster methods for electron affinities of closed-shell molecules.

We investigate performance of the equation-of-motion coupled-cluster method at the single and doubles level (EOM-CCSD) and a series of approximate methods based on EOM-CCSD on electron affinities (EA) of closed-shell cations and neutral molecules with positive and negative EAs in this work. Our results confirm that P-EOM-MBPT2 can provide reasonable EAs when molecules with significant multireference character are not considered and its mean absolute error on EAs of these molecules is around or less than 0.2 eV. Its accuracy is comparable to that of the more expensive EOM-CCSD(2) method. Results of EOM-CCSD(2), P-EOM-MBPT2, and CIS(D∞) indicate that the [[H, ac +], T2] term in the 1h2p-1h block is more important on EAs than the term neglected in the 1h2p-1h2p block in P-EOM-MBPT2. We proposed an economical method where EAs from CIS(D∞) are corrected by treating this [[H, ac +], T2] term in the 1h2p-1h block perturbatively [corr-CIS(D∞)]. EAs with corr-CIS(D∞) agree very well with those of P-EOM-MBPT2 with a difference of less than 0.02 eV. Computational scaling of this method is N4 for the iterative part and N5 for some non-iterative steps. Its storage requirement is only of OV3. Corr-CIS(D∞) is an economical and reliable method on EAs, and it can be applied to EAs of large molecules.

Properties of closed-shell superheavy element hydrides and halides using coupled-cluster method and density functional theory with spin-orbit coupling.

We report bond lengths, force constants, and dissociation energies for a series of closed-shell superheavy element monohydrides and halides at the singles and doubles level with perturbative triples (CCSD(T)) using recently developed relativistic effective core potentials in this work. CCSD(T) results with spin-orbit coupling (SOC) included in self-consistent field (SCF) calculations provide highly accurate estimates for properties of these molecules. Trends as well as SOC effects on properties of these molecules are presented. Performance of the coupled-cluster (CC) approach with SOC included in post-SCF calculations (SOC-CC) on these superheavy element molecules is evaluated. Our results show that SOC-CCSD results are in excellent agreement with those of KR-CCSD, while the error of SOC-CCSD(T) is larger, particularly for molecules containing element 114. Density functional theory results with various exchange-correlation (XC) functionals for these superheavy element molecules are also compared with those of CCSD(T). PBE0 is shown to be able to give rise to results that agree best with those of CCSD(T) in scalar-relativistic calculations among the investigated XC functionals. On the other hand, B97-3 is the best XC functional when SOC is considered in calculations.

Unraveling Key m6A Modification Regulators Signatures in Postmenopausal Osteoporosis through Bioinformatics and Experimental Verification.

OBJECTIVE: Bone marrow mesenchymal stem cells (BMSCs) show significant potential for osteogenic differentiation. However, the underlying mechanisms of osteogenic capability in osteoporosis-derived BMSCs (OP-BMSCs) remain unclear. This study aims to explore the impact of YTHDF3 (YTH N6-methyladenosine RNA binding protein 3) on the osteogenic traits of OP-BMSCs and identify potential therapeutic targets to boost their bone formation ability. METHODS: We examined microarray datasets (GSE35956 and GSE35958) from the Gene Expression Omnibus (GEO) to identify potential m6A regulators in osteoporosis (OP). Employing differential, protein interaction, and machine learning analyses, we pinpointed critical hub genes linked to OP. We further probed the relationship between these genes and OP using single-cell analysis, immune infiltration assessment, and Mendelian randomization. Our in vivo and in vitro experiments validated the expression and functionality of the key hub gene. RESULTS: Differential analysis revealed seven key hub genes related to OP, with YTHDF3 as a central player, supported by protein interaction analysis and machine learning methodologies. Subsequent single-cell, immune infiltration, and Mendelian randomization studies consistently validated YTHDF3's significant link to osteoporosis. YTHDF3 levels are significantly reduced in femoral head tissue from postmenopausal osteoporosis (PMOP) patients and femoral bone tissue from PMOP mice. Additionally, silencing YTHDF3 in OP-BMSCs substantially impedes their proliferation and differentiation. CONCLUSION: YTHDF3 may be implicated in the pathogenesis of OP by regulating the proliferation and osteogenic differentiation of OP-BMSCs.

MXenes induced formation of Ni-MOF microbelts for high-performance supercapacitors.

For the sake of developing new energy storage devices for satisfying the energy needs of the modern society, we herein report an innovative MXene-induced strategy to synthesize Ti3C2Tx MXenes/Ni based metal-organic framework composites (Ti3C2Tx/Ni-MOFs) for high-performance supercapacitors. The two-dimensional (2D) MXenes with oxygen-containing groups on the surface can be used as structure-directing agents to tune the Ni-MOFs into 2D microbelts. The presence of MXenes cannot only improve conductivity of the composite but also provide additional electric double layer capacitance and faradaic pseudocapacitance. The 2D Ni-MOF microbelts can offer rich activity sites for the faradaic redox reactions and shorten the ion transport path. Taking advantages of synergistic effects of Ni-MOF microbelts and Ti3C2Tx MXenes, the prepared Ti3C2Tx/Ni-MOFs electrode shows a good electrochemical performance with 1124 F g-1 at the current density of 1 A g -1 and 62% rate capability at 20 A g -1. This work can offer a new insight to design 2D MOF belts as high-performance electrode materials for supercapacitors.

[Prognosis of patients with intracerebral hemorrhage].

OBJECTIVE: To study the related factors of patients with intracerebral hemorrhage (ICH) so as to guide treatment and predict prognosis. METHODS: The prognostic factors of 463 cases with intracerebral hemorrhage were analyzed with single factor and Logistic regression analyses. RESULTS: Age, Glasgow coma scale, amount of hemorrhage, NIHSS score, mean arterial blood pressure, with or without ventricular breakage, with or without midline shift and the incidence of complications at random blood glucose levels were analyzed for the correlation with the prognosis of patients. The poor prognosis group had significant differences with the good prognosis group with regards to these factors. The average age of patients with a poor prognosis was 71 years old, the average hematoma volume 29 ml and the average GCS score 11.2 versus 65 years old, 15 ml, 15.1 for those with a good prognosis (P < 0.05). Logistic regression analysis showed that age, amount of hemorrhage and disturbance of consciousness was an independent adverse prognostic factor for cerebral hemorrhage at three months. The OR values were 1.32, 8.66 and 1.08 respectively. CONCLUSION: The etiologies of ICH are diverse. Maintaining normal blood pressure is an important preventive measure for ICH. Hematoma volume, disturbance of consciousness and age may be used to predict the prognosis of cerebral hemorrhage.

Morphologic observation of mucosa-associated lymphoid tissue in the large intestine of Bactrian camels (Camelus bactrianus).

The structure and distribution of the mucosa-associated lymphoid tissue (MALT) throughout the large intestine of 10 Bactrian camels were comparatively studied by anatomical and histological methods. The results showed that Peyer's patches (PPs) were mainly located on the mucosal surfaces of the entire ileocecal orifice, the beginning of the cecum and the first third of the colon. The shape of PPs gradually changed from "scrotiform" to "faviform" along the large intestine with the scrotiform PP as the major type in the ileocecal orifice. The distribution density also gradually decreased from the ileocecal orifice to the colon. The histological observations further revealed that the MALT in the form of PPs or isolated lymphoid follicles (ILF) and lamina propria lymphocytes was mainly present in the lamina propria and submucosa from the entire ileocecal orifice, where the muscularis mucosa is usually incomplete, to the colonic forepart. In addition, lymphoid tissue was much more abundant in the lamina propria and submucosa of the ileocecal orifice as compared to the cecum and colon. Statistically, the MALT of the ileocecal orifice contained a higher number of lymphoid follicles (37.7/10 mm(2) ) than that of the cecum, colon, or rectum (P < 0.05). The germinal centers of the lymphoid follicles were clearly visible. Together, our data suggest that the ileocecal orifice constitutes the main inductive site for the mucosal immunity in the large intestine of the Bactrian camel; and that scrotiform PPs are likely to the result of long-term adaptation of the Bactrian camel to the harsh living environment.