The gaseous reaction of CH+NO 2 has been investigated experimentally. CH radical was generated by multiple photon photolysis of CHBr 3 at 248 nm. Vibrationally excited species of HCO (ν 3), CO( v ), CO 2 (ν 3), HNO ...The gaseous reaction of CH+NO 2 has been investigated experimentally. CH radical was generated by multiple photon photolysis of CHBr 3 at 248 nm. Vibrationally excited species of HCO (ν 3), CO( v ), CO 2 (ν 3), HNO (ν 1), OH( v ) were detected as emitters of CH+NO 2 reaction by time resolved Fourier transform spectroscope. Three exothermic reaction channels leading to HCO+NO, NH+CO 2, CO+HNO, are identified. The minor reaction leading to OH+NCO may also occur.展开更多
Density Functional Method （DFT） B3LYP was performed to study the isomeration mechanism of HNO2 at the 6-31++G**basis sets and at the same time the potential energy curves were tracked. The geometric configurations o...Density Functional Method （DFT） B3LYP was performed to study the isomeration mechanism of HNO2 at the 6-31++G**basis sets and at the same time the potential energy curves were tracked. The geometric configurations of reactants, intermediates, transition states and products were optimized at B3LYP/6-31++G** level and the energies were calculated by using QCISD（T）/6-31++G** method. The results show that the most stabilized geometry structure is trans-HONO（M2） and the secondary stable geometric structure is HNO （O）.For other isomers, HNO（O）、HNOO and HO（O）N, are also characterized with a strong stability. In certain conditions, isomerization between all the isomers can be performed.展开更多
Long-term measurements of SO2 and HNO3, particularly those from the background sites, are rarely reported. We present for the first time the long-term measurements of SO2 and HNO3 at Waliguan （WLG）, the only global ...Long-term measurements of SO2 and HNO3, particularly those from the background sites, are rarely reported. We present for the first time the long-term measurements of SO2 and HNO3 at Waliguan （WLG）, the only global baseline station in the back-land of the Eurasian Continent. The concentrations of SO2 and HNO3 were observed at WLG from 1997 to 2009. The observed annual mean concentrations of SO2 and HNO3 at WLG were 1.28 ± 0.41 and 0.22 ± 0.19 μg/m3, respectively. The HNO3 concentrations were much higher in warmer seasons than in colder seasons, while the SO2 concentrations showed a nearly reversed seasonal pattern. In most months, the concentration of HNO3 was significantly correlated with that of SO2, suggesting that some common factors influence the variations of both gases and the precursors of HNO3 may partially be from the SO2-emitting sources. The SO2 concentration had a very significant （P 〈 0.0001） decreasing trend （-0.2 μg/（m3.yr）） in 1997-2002, but a significant （P 〈 0.05） increasing trend （＋0.06 μg/（m3-yr）） in 2003-2009. The HNO3 concentration showed no statistically significant trend during 1997-2009. While the decrease of SO2 in 1997-2002 agrees with the trend of global SO2 emissions, the increase in 2003-2009 is not consistent with the decreasing trends in many other regions over the world. Trajectory analysis suggests that the airmasses from the northern Qinghai-Tibetan Plateau and the Takla Makan Desert regions contributed significantly to the increasing trends of SO2 and HNO3 at WLG in 2003-2009, with a rate of ＋0.13 μg/（m3.yr） and ＋0.007μg/（m3.yr）, respectively.展开更多
文摘The gaseous reaction of CH+NO 2 has been investigated experimentally. CH radical was generated by multiple photon photolysis of CHBr 3 at 248 nm. Vibrationally excited species of HCO (ν 3), CO( v ), CO 2 (ν 3), HNO (ν 1), OH( v ) were detected as emitters of CH+NO 2 reaction by time resolved Fourier transform spectroscope. Three exothermic reaction channels leading to HCO+NO, NH+CO 2, CO+HNO, are identified. The minor reaction leading to OH+NCO may also occur.
文摘Density Functional Method （DFT） B3LYP was performed to study the isomeration mechanism of HNO2 at the 6-31++G**basis sets and at the same time the potential energy curves were tracked. The geometric configurations of reactants, intermediates, transition states and products were optimized at B3LYP/6-31++G** level and the energies were calculated by using QCISD（T）/6-31++G** method. The results show that the most stabilized geometry structure is trans-HONO（M2） and the secondary stable geometric structure is HNO （O）.For other isomers, HNO（O）、HNOO and HO（O）N, are also characterized with a strong stability. In certain conditions, isomerization between all the isomers can be performed.
基金supported by the National Natural Science Foundation of China(No. 21177157)the Basic Research Fund of Chinese Academy of Meteorological Sciences (No. 2011CX001,2011Z003)+1 种基金China Meteorological Administration(No. GYHY201106023)the Desert Meteorological Foundation of China Meteorological Administration (No.Sqj2010012)
文摘Long-term measurements of SO2 and HNO3, particularly those from the background sites, are rarely reported. We present for the first time the long-term measurements of SO2 and HNO3 at Waliguan （WLG）, the only global baseline station in the back-land of the Eurasian Continent. The concentrations of SO2 and HNO3 were observed at WLG from 1997 to 2009. The observed annual mean concentrations of SO2 and HNO3 at WLG were 1.28 ± 0.41 and 0.22 ± 0.19 μg/m3, respectively. The HNO3 concentrations were much higher in warmer seasons than in colder seasons, while the SO2 concentrations showed a nearly reversed seasonal pattern. In most months, the concentration of HNO3 was significantly correlated with that of SO2, suggesting that some common factors influence the variations of both gases and the precursors of HNO3 may partially be from the SO2-emitting sources. The SO2 concentration had a very significant （P 〈 0.0001） decreasing trend （-0.2 μg/（m3.yr）） in 1997-2002, but a significant （P 〈 0.05） increasing trend （＋0.06 μg/（m3-yr）） in 2003-2009. The HNO3 concentration showed no statistically significant trend during 1997-2009. While the decrease of SO2 in 1997-2002 agrees with the trend of global SO2 emissions, the increase in 2003-2009 is not consistent with the decreasing trends in many other regions over the world. Trajectory analysis suggests that the airmasses from the northern Qinghai-Tibetan Plateau and the Takla Makan Desert regions contributed significantly to the increasing trends of SO2 and HNO3 at WLG in 2003-2009, with a rate of ＋0.13 μg/（m3.yr） and ＋0.007μg/（m3.yr）, respectively.
