Reaction resonance or Feshbach resonance in polyatomic reaction is one of the most fascinating phenomena in chemical reaction dynamics. The HO+CH4→HO+CH3 reaction is one of the pivotal polyato-mic reactions concerned...Reaction resonance or Feshbach resonance in polyatomic reaction is one of the most fascinating phenomena in chemical reaction dynamics. The HO+CH4→HO+CH3 reaction is one of the pivotal polyato-mic reactions concerned with both the experimental and theoretical scientists. Reaction probabilities and other dynamic properties of this system were calculated with quantum scattering theory method, but a simple QH(v)+HO(j)→Q+H2O(m,n) reaction model was used, in which only three degrees of freedom and the rotating of OH were considered while making CH3 as a pseudo atom. In this paper, by an ab initio method, partial potential energy surface(PPES) was constructed and all the 15 internal degrees-freedom were given. Feshbach resonance mechanism of this reaction can be obtained by the dynamic Eyring Lake on the PPES and the lifetime of the reactive resonance-state can be estimated using the gap of the vibrational energy levels of transient collision complex in the critical transition-state region. Above interesting dynamic properties would not be given by simple pseudo atomic reaction model.展开更多
Heat capacities of the rare-earth complex with glycine [Ho(Gly)3Cl3·3H2O] were measured with a high-precision automatic adiabatic calorimeter over the temperature range from 78 to 348 K.In the experimental temper...Heat capacities of the rare-earth complex with glycine [Ho(Gly)3Cl3·3H2O] were measured with a high-precision automatic adiabatic calorimeter over the temperature range from 78 to 348 K.In the experimental temperature range,the heat capacities increased in a smooth and continuous manner and no phase transition or thermal anomaly occurred.Therefore,the sample was stable in the above temperature range.The values of experimental heat capacities were fitted to a polynomial equation with least square method and ...展开更多
This study focuses on the preparation of nanostructured holmium oxide via the decomposition of holmium acetate precursor utilizing the non-isothermal strategy. Thermogravimetric analysis(TGA) was used to follow up the...This study focuses on the preparation of nanostructured holmium oxide via the decomposition of holmium acetate precursor utilizing the non-isothermal strategy. Thermogravimetric analysis(TGA) was used to follow up the various thermal events involved in the decomposition process. Dehydration completes approximately at 150℃, which is followed by the decomposition of the anhydrous acetate leading to the formation of holmium oxide. Based on the TGA results the acetate precursor was heated non-isothermally at the temperature range of 150 e700℃. The obtained solids were characterized using powder X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), Fourier transform infrared spectroscopy(FT-IR), field-emission scanning electron microscopy(FE-SEM) and transmission electron microscopy(TEM). It is found that nanocrystalline Ho_2 O_3 starts to form at 500℃ and presents the only phase detected at the 500 e700℃ range. The electrical conductivity of the solids that form at the temperature range of 300 e700℃ was investigated. The obtained values were correlated with the observed structural modifications accompanying the heat treatment. The electrical conductivity of the Ho_2 O_3 samples prepared at 500, 600 and 700℃ reaches the values of 1.92 × 10^(-7), 1.61 × 10^(-7) and 8.33 × 10^(-8) Ω^(-1)cm^(-1) at a measuring temperature of 500℃, respectively. These values are potentially advantageous for high-resistivity devices.展开更多
The strong yellow upconversion （UC） light emission was observed in Ho3＋/yb3＋ co-doped Gd2M0309 phosphor under the excitation of 980 nm diode laser. The phosphors were synthesized by the traditional solid-state rea...The strong yellow upconversion （UC） light emission was observed in Ho3＋/yb3＋ co-doped Gd2M0309 phosphor under the excitation of 980 nm diode laser. The phosphors were synthesized by the traditional solid-state reaction method. The structures of the samples were characterized by X-ray diffraction （XRD）. Under 980 nm excitation, Ho3＋/yb3＋ co-doped Gd2Mo3O9 exhibited strong yellow UC emission based on the green emission near 541 nm generated by 5F4,5S2→5i8 transition and the strong red emission around 660 nm generated by 5F5→5I8 transition, which assigned to the intra-4f transitions of Ho3＋ ions. The doping concentrations of Ho3＋ and Yb3＋ were determined to be 0.01 mol Ho3＋ and 0.2 mol Yb3＋ for the strongest yellow emission. Then the dependence of UC emis- sion intensity on excitation power density showed that the green and red UC emissions were involved in two-photon process. The possible UC mechanisms for the strong yellow emission were also investigated. The result indicated that this material was a promis- ing candidate for the application in the yellow display field.展开更多
文摘Reaction resonance or Feshbach resonance in polyatomic reaction is one of the most fascinating phenomena in chemical reaction dynamics. The HO+CH4→HO+CH3 reaction is one of the pivotal polyato-mic reactions concerned with both the experimental and theoretical scientists. Reaction probabilities and other dynamic properties of this system were calculated with quantum scattering theory method, but a simple QH(v)+HO(j)→Q+H2O(m,n) reaction model was used, in which only three degrees of freedom and the rotating of OH were considered while making CH3 as a pseudo atom. In this paper, by an ab initio method, partial potential energy surface(PPES) was constructed and all the 15 internal degrees-freedom were given. Feshbach resonance mechanism of this reaction can be obtained by the dynamic Eyring Lake on the PPES and the lifetime of the reactive resonance-state can be estimated using the gap of the vibrational energy levels of transient collision complex in the critical transition-state region. Above interesting dynamic properties would not be given by simple pseudo atomic reaction model.
基金supported by the National Natural Science Foundation of China(20373072,20753002)
文摘Heat capacities of the rare-earth complex with glycine [Ho(Gly)3Cl3·3H2O] were measured with a high-precision automatic adiabatic calorimeter over the temperature range from 78 to 348 K.In the experimental temperature range,the heat capacities increased in a smooth and continuous manner and no phase transition or thermal anomaly occurred.Therefore,the sample was stable in the above temperature range.The values of experimental heat capacities were fitted to a polynomial equation with least square method and ...
文摘This study focuses on the preparation of nanostructured holmium oxide via the decomposition of holmium acetate precursor utilizing the non-isothermal strategy. Thermogravimetric analysis(TGA) was used to follow up the various thermal events involved in the decomposition process. Dehydration completes approximately at 150℃, which is followed by the decomposition of the anhydrous acetate leading to the formation of holmium oxide. Based on the TGA results the acetate precursor was heated non-isothermally at the temperature range of 150 e700℃. The obtained solids were characterized using powder X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), Fourier transform infrared spectroscopy(FT-IR), field-emission scanning electron microscopy(FE-SEM) and transmission electron microscopy(TEM). It is found that nanocrystalline Ho_2 O_3 starts to form at 500℃ and presents the only phase detected at the 500 e700℃ range. The electrical conductivity of the solids that form at the temperature range of 300 e700℃ was investigated. The obtained values were correlated with the observed structural modifications accompanying the heat treatment. The electrical conductivity of the Ho_2 O_3 samples prepared at 500, 600 and 700℃ reaches the values of 1.92 × 10^(-7), 1.61 × 10^(-7) and 8.33 × 10^(-8) Ω^(-1)cm^(-1) at a measuring temperature of 500℃, respectively. These values are potentially advantageous for high-resistivity devices.
基金Project supported by National Natural Science Foundation of China (20976002)Beijing Municipal Natural Science Foundation(2122012)+2 种基金Key Projects for Science and Technology of Beijing Education Commission (KZ201310011013)Project of Transformation and Industrialization of College Scientific & Technological AchievementsProjects of the Combination of Manufacture,Education & Research of Guangdong Province (2011B090400100)
文摘The strong yellow upconversion （UC） light emission was observed in Ho3＋/yb3＋ co-doped Gd2M0309 phosphor under the excitation of 980 nm diode laser. The phosphors were synthesized by the traditional solid-state reaction method. The structures of the samples were characterized by X-ray diffraction （XRD）. Under 980 nm excitation, Ho3＋/yb3＋ co-doped Gd2Mo3O9 exhibited strong yellow UC emission based on the green emission near 541 nm generated by 5F4,5S2→5i8 transition and the strong red emission around 660 nm generated by 5F5→5I8 transition, which assigned to the intra-4f transitions of Ho3＋ ions. The doping concentrations of Ho3＋ and Yb3＋ were determined to be 0.01 mol Ho3＋ and 0.2 mol Yb3＋ for the strongest yellow emission. Then the dependence of UC emis- sion intensity on excitation power density showed that the green and red UC emissions were involved in two-photon process. The possible UC mechanisms for the strong yellow emission were also investigated. The result indicated that this material was a promis- ing candidate for the application in the yellow display field.
