Adsorption mechanisms of different toxic molecular gases on intrinsic C2N and Ti-C2N-V monolayer: a DFT study.

Recently, the excessive emission of chemical toxic gases such as nitrogen trifluoride (NF3), ammonia (NH3), phosgene (COCL2), and benzene (C6H6) has caused serious environmental problems. Adsorption of these chemical toxic gas molecules is a promising method to reduce environmental pollution. In this work, density functional theory (DFT) calculations are used to investigate the adsorption properties of these chemical toxic molecules on intrinsic C2N and Ti-C2N-V monolayer. The results show that NF3, NH3, C6H6, and COCL2 can all be adsorbed to the intrinsic C2N monolayer with weak adsorption energy, while the adsorption properties of these gas molecules were greatly improved after doping Ti atom. The adsorption energy of NH3, C6H6, COCL2, and NF3 increased from - 0.585, - 0.432, - 0.633, and - 0.362 eV to - 2.214, - 1.699, - 1.822, and - 0.799 eV, respectively, which increased by 2 ~ 4 times compared with that before doping. Besides, the results of the electron distribution, work function, the total density of states (TDOS), and the partial density of states (PDOS) analysis indicate that the doped Ti atom can be used as a bridge to connect the adsorbed molecules with the C2N-V monolayer, strengthen their interaction, and significantly improve the adsorption capacity. Therefore, Ti-doped C2N-V (Ti-C2N-V) monolayer is a promising adsorbent for the enrichment and utilization of harmful gases.

Absorption Spectra of Acetylene, Vinylidene, and Their Deuterated Isotopologues on Ab Initio Potential Energy and Dipole Moment Surfaces.

The absorption spectra of acetylene (HCCH) and vinylidene (H2CC) as well as their deuterated isotopologues are investigated theoretically on a near spectroscopically accurate full-dimensional potential energy surface reported in an earlier publication, using dipole moment surfaces reported in this work, which are constructed with a neural network method from a large number of ab initio data points. These global surfaces cover not only the deep acetylene well but also the vinylidene well, as well as the transition region between the two isomers. The agreement with available experimental data for acetylene is excellent, validating both the potential energy surface and the dipole moment surfaces. The infrared spectra of vinylidene and its deuterated isotopologues are predicted. The potential and dipole moment surfaces lay the foundation for future spectroscopic studies of the acetylene-vinylidene isomerization involving large-amplitude motions.

Quantum dynamical investigation of product state distributions of the F + CH3OH → HF + CH3O reaction via photodetachment of the F-(HOCH3) anion.

The photodetachment of the F-(HOCH3) anion, which sheds light on the post-transition-state dynamics of the F + CH3OH → HF + CH3O reaction, is investigated using a reduced-dimensional quantum wave packet method on ab initio based potential energy surfaces for both the neutral and anionic species. The detachment of an electron in the anion precursor produces both bound and resonance species in a hydrogen-bonded potential well in the product channel, in qualitative agreement with the photoelectron-photofragment coincidence (PPC) spectrum. The measured photoelectron-photofragment coincidence spectroscopy is reproduced by the quantum calculations. Our results indicated that the HF product is vibrationally excited, while the OCH3 product is internally cold, thus providing unambiguous assignments of the experimental spectrum.

Activation of Reactions in the Complex Region Using Microwave Irradiation.

Many mode-specific behaviors in the gas phase and at the gas-surface interface have been reported in the past decades. Infrared activation of a reagent vibrational mode is often used to study these reactions. In this work, an inexpensive and easily applied scheme using microwave irradiation is proposed for activating complex-forming reactions by transferring populations between closely spaced resonances. The important combustion reaction of H + O2 ↔ O + OH is used as a model system to demonstrate the feasibility of the proposed approach. The existence of a nonzero transition dipole moment matrix element between two highly excited resonance states separated by a small energy gap in the model system may allow one to use microwave irradiation to intervene and control the model reaction. The high energy resonance states of the model reaction can also release their energy by photon emission, which is in agreement with the experimentally observed chemiluminescence process.

Feshbach resonances in the exit channel of the F + CH3OH → HF + CH3O reaction observed using transition-state spectroscopy.

The transition state governs how chemical bonds form and cleave during a chemical reaction and its direct characterization is a long-standing challenge in physical chemistry. Transition state spectroscopy experiments based on negative-ion photodetachment provide a direct probe of the vibrational structure and metastable resonances that are characteristic of the reactive surface. Dynamical resonances are extremely sensitive to the topography of the reactive surface and provide an exceptional point of comparison with theory. Here we study the seven-atom F + CH3OH → HF + CH3O reaction using slow photoelectron velocity-map imaging spectroscopy of cryocooled CH3OHF- anions. These measurements reveal spectral features associated with a manifold of vibrational Feshbach resonances and bound states supported by the post-transition state potential well. Quantum dynamical calculations yield excellent agreement with the experimental results, allow the assignment of spectral structure and demonstrate that the key dynamics of complex bimolecular reactions can be captured with a relatively simple theoretical framework.

Quantum Dynamics of Vinylidene Photodetachment on an Accurate Global Acetylene-Vinylidene Potential Energy Surface.

Vinylidene is a high-energy isomer of acetylene, and the rearrangement of bonds in the two species serves as a prototype for isomerization reactions. Here, a full-dimensional quantum mechanical study of the vinylidene vibration is carried out on a recently developed global acetylene-vinylidene potential energy surface by simulating the photodetachment dynamics of the vinylidene anion. Several low-lying vibrational levels of the anion were first determined on a new ab initio based potential energy surface, and their photoelectron spectra were obtained within the Condon approximation. The vibrational features of the vinylidene isomer are found to agree well with the experiment in both positions and intensities, validating the global acetylene-vinylidene potential energy surface.

[Upregulated voltage-gated potassium channel Kv1.3 on the CD4+CD28null T lymphocyte from patients with acute coronary syndrome].

OBJECTIVE: The purpose of our study is to observe the voltage-gated potassium channel Kv1.3 expression on CD4+CD28null T cells from the peripheral blood of ACS patients by the patch clamp technique. METHODS: Kv1.3 potassium channels expression from 17 patients with ACS and 11 healthy age-matched normal controls was detected in single cell (CD4+CD28null T cells and CD4+CD28+ T cells) by fluorescence microscopy and patch clamp. RESULTS: The percent of CD4+CD28nullT cells are higher in the ACS (6.97% +/- 2.05%) than that in the controls (1.38% +/- 0.84%, P < 0.05). The concentration of hsCRP is directly correlated with the number of the CD4+CD28null T cells in the ACS (r = 0.52, P < 0.05). The conductance [(6.89 +/- 1.17) nS vs. (3.36 +/- 0.66) nS], dens [(1.95 +/- 0.80) n/microm2 vs. (1.13 +/- 0.57) n/microm2] and numbers [(574.5 +/- 97.6) n/cell vs. (280.3 +/- 55.3) n/cell] of the Kv1.3 channels on the CD4+CD28null T cells are significantly higher than those on the CD4+CD28+ T cells (all P < 0.01) in ACS patients, but were similar on CD4+CD28+ T cells between ACS patients and controls. CONCLUSION: The CD4+CD28null T cells in the ACS and the numbers of Kv1.3 channels on the CD4+CD28null T cells from the ACS patients are significantly upregulated and might contribute to the pathogenesis of ACS.

[T-lymphocyte voltage dependent K(+) channel is upregulated in patients with acute coronary syndrome].

OBJECTIVE: To determine current density of voltage-gated potassium channels and Kv1.3 express in T-lymphocyte derived from patients with acute coronary syndrome (ACS). METHODS: Peripheral blood mononuclear cells were collected from 12 patients with ACS and 10 control donors. Whole-cell patch clamp technique was used to record the outward K(+) currents (IK) and western blots technique was used to detect the express of Kv1.3 protein in lymphocyte. RESULTS: (1) The current density of voltage-gated potassium channel was significantly higher in ACS patients [(269 +/- 94) pA/pF] than in controls [(191 +/- 64) pA/pF, P < 0.01] while membrane capacitance was similar between the two groups. (2) Kv1.3 protein expression was also significantly increased in ACS patients than in controls (P < 0.01). CONCLUSION: The lymphocyte voltage-gated potassium channel is upregulated in patients with ACS suggesting a role of Kv activation in the pathophysiology of ACS.