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Reaction resonances, or transiently stabilized transition-state structures, have proven highly challenging to capture experimentally. Here, we used the highly sensitive H atom Rydberg tagging time-of-flight method to conduct a crossed molecular beam scattering study of the F + H 2 → HF + H reaction with full quantum-state resolution. Pronounced forward-scattered HF products in the v ′ = 2 vibrational state were clearly observed at a collision energy of 0.52 kcal/mol; this was attributed to both the ground and the first excited Feshbach resonances trapped in the peculiar HF( v ′ = 3)-H′ vibrationally adiabatic potential, with substantial enhancement by constructive interference between the two resonances.

A global three dimensional potential energy surface for the F+H2HF+H reaction has been developed by spline interpolation of about 15,000 symmetry-unique ab initio points, obtained from the multi-reference configuration interaction level with Davidson correction using the aug-cc-pV5Z basis set. In the entrance channel the spin-orbit coupling energy is also included.

Vector hydrophone can synchronously receive the sound scalar field and the vector field information at a single point, which increases the variety and the quantity of the received sound information. Vector field information is beneficial to improve the performance of underwater acoustic devices or systems. In summer of 2014, a Long-Range Ocean Acoustic Propagation Experiment was carried out in deep sea. A deep-water vector hydrophone designed by Harbin Engineering University was located at the depth of 3146 m, which measured all the three components of particle velocities as well as the sound pressure in the acoustic field. The scalar and vector receptions of convergence zone arrivals and deep shadow zone arrivals were acquired for hundreds of kilometers in the experiment. The analyzed transmission loss results of the experimental data are described and compared with the predictions by a 2-D parabolic equation (PE) model, which is also called RAM. The comparisons show that the RAM-PE model is efficient to simulate both scalar field and vector field in deep water. Moreover, experiment results demonstrate that the deep-water vector hydrophone performs well to measure sound pressure signal and sound vector signal in deep water.

Converged differential and integral cross sections are reported for the H + O2 → OH + O reaction on an improved potential energy surface of HO2(X2A′′) using a dynamically exact quantum wave packet method and Gaussian weighted quasi-classical trajectory method. The complex-forming mechanism is confirmed by strong forward and backward scattering peaks and by highly inverted OH rotational state distributions. Both the quantum and classical results provide strong evidence for nonstatistical behavior in this important reaction.

The authors report a global potential energy surface for the ground electronic state of HO(2)(X (2)A(")), which improves upon the XXZLG potential [Xu and et al., J. Chem. Phys. 122, 244305 (2005)] with additional high-level ab initio points for the long-range interaction potential in the O+OH channel. Exact J=0 quantum mechanical reaction probabilities were calculated on the new potential and the rate constant for the title reaction was obtained using a J-shifting method. The calculated rate constant is in good agreement with available experimental values and our results predict a significantly lower rate at temperature range below 30 K, offering a possible explanation for the "interstellar oxygen problem."

Two global analytical potential energy surfaces for the HO2(X2A") system have been developed by fitting approximately 15,000 ab initio points at the icMRCI+Qaug-cc-pVQZ level of theory, using the reproducing kernel Hilbert space method. One analytical potential is designed to give a very accurate representation of the low energy range that determines the vibrational spectrum, while the other attempts to provide a fast and uniformly accurate potential function for reaction dynamics. The quality of the fitted potential functions is confirmed by good agreement of the (J=0) HO2 vibrational spectrum and (J=0) quantum reaction probability for the H+O2(ji=0,nui=0) reaction with those obtained using the spline fitted potential. Quasiclassical trajectory calculations carried out on the new potential energy surface provided the reaction probability with a zero impact parameter (b=0), which is in reasonably good agreement with the J=0 quantum results.

Full quantum state resolved scattering of the F atom reaction with H(2)(j=0) and H(2)(j=1) was investigated at the collision energies of 0.19 and 0.56 kcalmol. Dramatic difference between the dynamics for the F+H(2)(j=0,1) reactions at both collision energies have been observed. Forward scattering HF(v(')=2) products have been observed unambiguously for the F+H(2)(j=1) reaction at low collision energies, which was attributed to the Feshbach resonances. This study provides a unique case of reaction resonances involving a rotationally excited reagent.

The aim of the present study was to investigate how some cooking methods and in vitro digestion influence antioxidant activity, total phenols (TP), and total flavonoids (TF) of faba bean and azuki bean. Soaking caused a significant decrease (27.60-38.15%) in the bioavailability of TP of dry faba beans (FB). Soaking in cold water resulted in a significant decrease in TP bioavailability of dry azuki beans (AB). TF content was well retained in AB cooked without soaking but was not detected in FB after in vitro digestion. FB soaked in hot water and cooked with the addition of NaHCO3 showed thegreatest inhibition effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical (p< 0.05) after in vitro digestion. In vitro digestion caused increase in the antioxidant activity of both FB and AB.

The authors report accurate quantum mechanical studies of the O+OH reaction on the improved Xu-Xie-Zhang-Lin-Guo potential energy surface. The differential cross section was obtained at several energies near the reaction threshold using a time-independent method. The dominant forward and backward peaks in the angular distribution are consistent with a complex-forming mechanism, which is also confirmed by the extensive rotational excitation in the O2 product. However, the asymmetry of these peaks suggests a significant nonstatistical component. The initial state (upsilon i=0, j i=0) specified integral cross section, which was calculated up to 1.15 eV of collision energy using the Chebyshev wave packet method, shows no energy threshold and decreases with the increasing collision energy, consistent with the barrierless nature of the reaction. The resulting rate constant exhibits a negative temperature dependence for T100 K and decays as the temperature is lowered, in qualitative agreement with available experimental data.

A new global potential-energy surface for the ground electronic state of HO(2)(X(2)A(")) has been developed by three-dimensional cubic spline interpolation of more than 15 000 ab initio points, which were calculated at the multireference configuration-interaction level with Davidson correction using the augmented correlation-consistent polarized valence quadruple zeta basis set. Low-lying vibrational states were obtained in this new potential using the Lanczos method and assigned. The calculated vibrational frequencies are in much better agreement with the available experimental band origins than those obtained from a previous potential. In addition, rate constants for the H+O(2) O + OH reactions were obtained using a wave-packet-based statistical model. Reasonably good agreement with experimental data was obtained. These results demonstrate the accuracy of the potential.