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The anionic carbonyl complexes of groups IV and V metals are prepared in the gas phase using a laser vaporation-supersonic expansion ion source. The infrared spectra of the TM(CO)<sub>6,7</sub><sup>-</sup> (TM=Ti, Zr, Hf, V, Nb, Ta) anion complexes in the carbonyl stretching frequency region are measured by mass-selected infrared photodissociation spectroscopy. The six-coordinated TM(CO)<sub>6</sub><sup>-</sup> anions are determined to be the coordination saturate complexes for both the group IV and group V metals. The TM(CO)<sub>6</sub><sup>-</sup> complexes of group IV metals (TM=Ti, Zr, Hf) are 17-electron complexes having a <sup>2</sup>A<sub>1g</sub> ground state with D<sub>3d</sub> symmetry, while the TM(CO)<sub>6</sub><sup>-</sup> complexes of group V metals (TM=V, Nb, Ta) are 18-electron species with a closed-shell singlet ground state possessing O<sub>h</sub> symmetry. The energy decomposition analyses indicate that the metal-CO covalent bonding are dominated by TM-(d) → (CO)<sub>6</sub> π-backdonation and TM-(d)←(CO)<sub>6</sub> σ-donation interactions.
Vacuum ultraviolet photodissociation dynamics of N2O + hv → N2(X1Σg+) + O(1S0) in the short wavelength tail of D1Σ+ band have been performed using the time-sliced velocity-mapped ion imaging technique by probing the images of the O(1S0) photoproducts at a set of photolysis wavelengths from 121.47 to 123.95 nm. The product total kinetic energy release distributions, vibrational state distributions of the N2(X1Σg+) photofragments and angular anisotropy parameters have been obtained through analyzing the raw O(1S0) images. It is noted that an additional vibrationally excited photoproducts (3≤v≤8) with a Boltzmann-like feature start to appear except for the non-statistical component as the photolysis wavelength decreases to 123.25 nm, and the corresponding populations become more pronounced with decreasing of the photolysis wavelength. Furthermore, the vibrational state specific β-value at each photolysis wavelength exhibits a drastic fluctuation near β=1.75 at v<8, and decreases to a minimum as the vibrational quantum number further increases. While the overall β-value for the N2(X1Σg+) + O(1S0) channel presents a roughly monotonically increasing from the value of 1.63 at 121.47 nm to 1.95 at 123.95 nm. The experimental observations suggest that there is at least one fast nonadiabatic pathway from initially prepared D1Σ+ state to the dissociative state with bent geometry dominating to generate the additional vibrational structures at high photoexcitation energies.
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We calculate the interaction strength of the van der Waals force between two Rydberg atoms by applying the applications of quantum information processing using for Rydberg blockade. The alkali metals (Cs and K) in states of principal quantum number n were used to calculate the interaction strength. We use some possible angular momentum channels involving s, p, and d states for measuring interaction strength. The obtained results were then generalized for all angular momentum channels which mostly have small interactions and therefore a poor candidate for blockade experiments. The interaction strength in the atoms of Cs and K dipole matrix elements was calculated first and then relevant energy levels were determined by using the quantum defects theory. The radial wave function was calculated numerically with the integration of the radial Schrödinger equation. Also, the interaction coefficients of van der Waals for various channels were calculated here.
The kinetics of U(IV) produced by hydrazine reducting U(VI) with platinum as catalyst in nitric acid media was studied for revealing the reaction mechanism and optimizing the reaction process. Electron spin resonance (ESR) was used to determine the influence of nitric acid oxidation. The influence of nitric acid, hydrazine, U(VI) concentration, catalyst dosage and temperature on the reaction were studied. Concurrently, the simulation of the reaction process was performed using density functional theory (DFT). The results show that the influence of oxidation on the main reaction is limited when the concentration of nitric acid was below 0.5 mol/L. The reaction kinetics equation below the concentration of 0.5 mol/L is found as follows: –dc(UO22+)/dt) = kc0.5323(UO22+)c0.2074(N2H5+)c−0.2009(H+). When the temperature is 50°C, and the solid/liquid ratio r is 0.0667g/mL, the reaction kinetics constant is k = 0.00199 (mol/L) 0.4612/min. Between 20℃ and 80℃, with the increase of temperature, the reaction rate is gradually accelerated, and the reaction changes from chemically controlled to diffusion-controlled. The reaction process is simulated by DFT, and the influence of various factors on the reaction process is deduced. The reaction process and mechanism are determined according to the reaction kinetics and simulation results finally.
Rotating disk electrode systems are widely used to study the kinetics of electrocatalytic reactions that may suffer from insufficient mass transfer of the reactants. Kinetic current density (jk) at certain overpotential calculated by K-L equation is commonly used as the metrics to evaluate the activity of electrocatalysts. However, it is frequently found that the jl is not correctly identified in the literatures. Instead of jK, the measured current density normalized by diffusion limiting current density (j/jL) has also been frequently under circumstance where its validity is not justified. By taking ORR/HER/HOR as examples, we demonstrate that identify the actualjL for the same reaction under otherwise identical conditions from the experimental data is essential to accurately deduce jk. Our analysis reveals that j/jL is a rough activity metric which can only be used to qualitatively compare the activity trend under conditions that the mass transfer conditions and the roughness factor of the electrode are exactly the same. In addition, if one wants to use j/jL to compare the intrinsic activity, the concentration overpotential should be eliminated.
This work reports the systematic study of surface phenomenon and self-aggregation behavior of cationic surfactant cetyltrymethyl ammonium bromide (CTAB) with ammonium nitrate (NH4NO3) salt. Surface and thermodynamic properties of cationic surfactant CTAB with ammonium nitrate salt were investigated at different temperatures through different techniques like conductometry and surface tensiometery. The surface tension measurement was carried out to find out the critical micelle concentration (CMC), free energy of adsorption (?Gads), free energy of micellization (?Gm), minimum area per molecule (A) and surface excess concentration (Г). The study reveals that the process of micellization is spontaneous and exothermic in nature. Conductance measurement enabled us to determine CMC, degree of ionization (α), degree of counter ion binding (β). Upon addition of NH4NO3 to the surfactant solutions increase the values of α and β, although it lowers the values of CMC showing that the process of micellization is more favorable and spontaneous. The study is very helpful to develop better understanding about interaction between electrolyte and surfactant.
