In this paper, for the hydrogen abstraction reaction of HCHO by OH radicals assisted by water, formic acid, or sulfur acid, the possible reaction mechanisms and kinetics have been investigated theoretically using quantum chemistry methods and transition-state theory. The potential energy surfaces calculated at the CCSD(T)/6-311++G(df,pd)//MP2(full)/6-311++G(df,pd) levels of theory reveal that, due to the formation of strong hydrogen bond(s), the relative energies of the transition states involving catalyst are significantly reduced compared to that reaction without catalyst. However, the kinetics calculations show that the rate constants are smaller by about 3, 9, or 10 orders of magnitude for water, formic acid, or sulfur acid assisted reactions than that uncatalyzed reaction, respectively. Consequently, none of the water, formic acid, or sulfur acid can accelerate the title reaction in the atmosphere.

Ternary strategies show over 16% efficiencies with increased current/voltage owing to complementary absorption/aligned energy level contributions. However, poor understanding of how the guest components tune the active layer structures still makes rational selection of material systems challenging. In this study, two phthalimide based ultrawide bandgap polymer donor guests are synthesized. Parallel energies between the highest occupied molecular orbitals of host and guest polymers are achieved via incorporating selnophene on the guest polymer. Solid‐state 19F magic angle spinning nuclear magnetic spectroscopy, graze‐incidence wide‐angle X‐ray diffraction, elemental transmission electron microscopy mapping, and transient absorption spectroscopy are combined to characterize the active layer structures. Formation of the individual guest phases selectively improves the structural order of donor and acceptor phase. The increased electron mobility in combination with the presence of the additional paths made by the guest not only minimizes the influence on charge generation and transport of the host system but also contributes to increasing the overall current generation. Therefore, phthalimide based polymers can be potential candidates that enable the simultaneous increase of open‐circuit voltage and short‐circuit current‐density via fine‐tuning energy levels and the formation of additional paths for enhancing current generation in parallel‐like multicomponent organic solar cells.

In order to measure trace plutonium and its isotopes ratio (Pu/Pu) in environmental samples with a high uranium, an analytical method was developed using radiochemical separation for separation of plutonium from matrix and interfering elements including most of uranium and ICP-MS for measurement of plutonium isotopes. A novel measurement method was established for extensively removing the isobaric interference from uranium (UH and UH) and tailing of U, but significantly improving the measurement sensitivity of plutonium isotopes by employing NH/He as collision/reaction cell gases and MS/MS system in the triple quadrupole ICP-MS instrument. The results show that removal efficiency of uranium interference was improved by more than 15 times, and the sensitivity of plutonium isotopes was increased by a factor of more than 3 compared to the conventional ICP-MS. The mechanism on the effective suppress of U interference forPu measurement using NH-He reaction gases was explored to be the formation of UNH and UNH in the reactions of UH and U with NH, while no reaction between NH and Pu. The detection limits of this method were estimated to be 0.55 fg mL for Pu, 0.09 fg mL for Pu. The analytical precision and accuracy of the method for Pu isotopes concentration andPu/Pu atomic ratio were evaluated by analysis of sediment reference materials (IAEA-385 and IAEA-412) with different levels of plutonium and uranium. The developed method were successfully applied to determine Pu andPu concentrations and Pu/Pu atomic ratios in soil samples collected in coastal areas of eastern China.

In this study, the reaction mechanism and kinetics of the hydrogen abstraction and addition reactions of NCO with HCHO in the absence and presence of water have been investigated theoretically for the first time. Our theoretical results indicate that direct hydrogen abstraction is favored in the formation of HNCO instead of HOCN and the addition pathways are negligible with and without water. The rate constants calculated at the CCSD(T)/aug-cc-pVTZ//BH&HLYP/6-311++G(3df,3pd) level with zero-point energy correction range from 1.60 × 10(-12) to 4.99 × 10(-12) cm(3) molecule(-1) s(-1) between 220 and 769 K without water and are in good agreement with the available experimental values. However, with the inclusion of water, the rate constants are slower by 2-8 orders of magnitude than those of the reaction without water. Accordingly, the effect of water on the reaction of NCO with HCHO is negligible in the atmosphere.

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ABSTRACT:The mechanism for the OH ϩ 3-methylfuran reaction has been studied via ab initio calculations to investigate various reaction pathways on the doublet potential energy surface. Optimizations of the reactants, products, intermediates, and transition structures are conducted using the MP2 level of theory with the 6-311G(d,p) basis set. The single-point electronic energy of each optimized geometry is refined with G3MP2 and G3MP2B3 calculations. The theoretical study suggests that the OH ϩ 3-methylfuran reaction is dominated by the formation of HC(O)CHAC(CH 3 )CHOH (P7) and CH(OH)CHAC(CH 3 )C(O)H (P9), formed from two low-lying adducts, IM1 and IM2. The direct hydrogen abstraction pathways and the S N 2 reaction may play a minor or negligible role in the overall reaction of OH with 3-methylfuran.