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Although FNO has long been considered a computationally challenging molecule, no thorough study of this species has been performed with methods of electron correlation beyond second-order Mo\ller–Plesset perturbation theory (MP2) and the singles and doubles configuration interaction (CISD) method. We have investigated the equilibrium structure, vibrational spectra, and relative energetics of FNO using high-levels of ab initio theory. Methods include third and fourth-order Mo\ller–Plesset perturbation (MP3 and MP4), singles and doubles coupled-cluster (CCSD) theory, and the CCSD(T) method, which incorporates a perturbational estimate of the effects of connected triple excitations. The quadratic configuration interaction method including single, double, and triple excitations [QCISD(T)] method is also used. Computations using these methods are performed with medium and large basis sets. Geometries calculated at the Hartree–Fock level are grossly in error, while going to the CISD, MP3, MP4, and CCSD methods produces increasingly better results. The CCSD(T) and QCISD(T) methods yield quite accurate structures; surprisingly, the MP2 results are almost as good. The quality of the calculated relative energetics closely follows that of the structure predictions, except that the MP2 level of theory now performs slightly worse than MP3, MP4, and CCSD methods. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a global pollutant whose atmospheric deposition is a major input to the terrestrial and oceanic ecosystems. Gas‐particle partitioning (GPP) of gaseous oxidized mercury (GOM) redistributes speciated Hg between gas and particulate phase and can subsequently alter Hg deposition flux. Most 3‐dimensional chemical transport models either neglected the Hg GPP process or parameterized it with measurement data limited in time and space. In this study, CMAQ‐newHg‐Br (Ye et al., 2018, https://doi.org/10.1002/2017ms001161) was updated to CMAQ‐newHg‐Br v2 by implementing a new GPP scheme and the most up‐to‐date Hg redox chemistry and was run for the northeastern United States over January‐November 2010. CMAQ‐newHg‐Br v2 reproduced the measured spatiotemporal distributions of gaseous elemental mercury (GEM) and particulate bound mercury (PBM) concentrations and Hg wet deposition flux within reasonable ranges and simulated dry deposition flux in agreement with previous studies. The GPP scheme improved the simulation of PBM via increasing winter‐, spring‐ and fall‐time PBM concentrations by threefold. It also improved simulated Hg wet deposition flux with an increase of 2.1 ± 0.7 μgm2 in the 11‐month accumulated amount, offsetting half of the decreasing effect of the updated chemistry (−4.2 ± 1.8 μgm2). Further, the GPP scheme captured the observed Kp‐T relationship as reported in previous studies without using measurement data and showed advantages at night and in rural/remote areas where existing empirical parameterizations failed. Our study demonstrated CMAQ‐newHg‐Br v2 a promising assessment tool to quantify impacts of climate change and emission reduction policy on Hg cycling. Plain Language Summary: Mercury is a toxic global pollutant and can enter the food chain through atmospheric deposition to ecosystems. Atmospheric mercury was defined operationally in the forms of gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM) and particulate bound mercury (PBM). GEM is relatively inert, but GOM and PBM are highly soluble and readily removed from the air via deposition. GEM gets oxidized to GOM and GOM can be transformed to PBM through gas particle partitioning (GPP). CMAQ‐newHg‐Br v2 was updated from its predecessor via implementing the most up‐to‐date Hg redox chemistry and a new GPP scheme. The model improved the simulation of GEM, PBM, and Hg wet deposition. Most notably the model reproduced the observed partitioning coefficient and temperature relationship (Kp‐T) and improved nighttime and less polluted PBM simulations. CMAQ‐newHg‐Br v2 can be used to assess how climate change and emission reduction policy impact environmental Hg cycling. Key Points: CMAQ‐newHg‐Br was updated to version 2 with a new gas‐particle partitioning (GPP) scheme and the most up‐to‐date Hg redox chemistryCMAQ‐newHg‐Br v2 better simulated gaseous elemental mercury (GEM), particulate bound mercury (PBM) and Hg wet depositionThe new GPP scheme captured the observed Kp‐T relation not using measurement data and improved nighttime and less polluted simulations [ABSTRACT FROM AUTHOR]

An abstract of the article "An evaluation of the long-term effectiveness of two adult community-based group weight management interventions," by J. Gordon, T. Dibble, C. Adams, and E. McGee is presented.

Simultaneous measurements of absolute concentrations of H2O and OH radicals in an atmospheric AC discharge using continuous wave cavity ringdown spectroscopy (cw-CRDS) are reported. Formation of OH radicals and plasma temperatures are characterized by optical emission spectroscopy. The concentration of OH radical at the edge of the discharge plume at 380 K is measured by the cw-CRDS technique to be 1.1 ×1015 molecule cm-3. Ringdown measurements of the H2O (120-000) band and the OH first overtone around 1515 nm enable us to determine an OH generation yield, $\Phi =\frac{N_{\rm OH} }{N_{\rm H_2 O}}$, to be 4.8 ×10-3, where NOH and $$ N_{H_2 O} $$ are the number densities of OH and H2O, respectively. The minimum detectable absorption coefficient of the cw-CRDS system is 8.9 ×10-9 cm-1, which corresponds to a 1σ detection limit of OH number density of 1.2 ×1013 molecule cm-3 in the discharge. This experimental approach is demonstrated for the first time ever in an AC discharge, and can be applied in general to a variety of atmospheric plasmas to help study OH formation mechanisms and OH-related plasma applications. [ABSTRACT FROM AUTHOR]

We present results of density functional calculations on ClOO using the local density approximation (LDA) and the Becke–Lee–Yang–Parr functional (BLYP). The accuracy of computed geometries and vibrational frequencies appears comparable to that achieved with very high quality single-determinant methods [QCISD(T)]. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]