He(23S1)、Ne(3P0,2)与NH3的传能动力学

在分子束条件下利用化学发光技术研究了亚稳态惰性气体原子He（23S1）和Ne（3P0，2）与NH3碰撞的解离激发反应．He（23S1）与NH3的反应中观察到NH（A－X，c－a，c－b），NH＋（B－X）和H*－Balmer发射．对NH（A－X，c－a）的谱图进行了拟合．分析NH（c－b）谱发现NH（c）倾向于生成具有f对称性的转动能级，NH3可能是经由一个NH2中间体分两步解离，这与121．6nm光解NH3时的倾向性正好相反．利用参比反应测得生成NH（A，c）的速度为k＝1．0×10－11cm3•s－1．He（23S1）与NH3生成的NH（A，v’＝1）的转动激发比v’＝0时要高，根据含角动量守恒的相空间理论，其生成过程可能具有较大的解离半碰撞参数．Ne（3P0，2）与NH3反应只有NH（A－X，c－a）发射，NH（A，c）的振转布居可由简单相空间理论三体解离模式解释．     

NH2(A2A1,090,423)的电子猝灭和转动态-态传能

在束 气和束 束实验条件下,详细研究了NH2(A1,090,423)自由基分别与Ar,N2,O2和NH3碰撞引起的电子态猝灭和转动态 态传能,获得了总的猝灭截面σQ (分别为≤0.17、0.26、0.30和0.48 nm2),以及相对转动态 态传能截面.利用碰撞络合物模型计算的电子猝灭截面与实验测得的截面具有基本相同的趋势,表明长程吸引势在猝灭过程中起着重要的作用.同时还发现,转动态 态传能中相对截面随着碰撞对的折合质量的减小而下降.由于NH3具有较大的偶极矩以及O2的开壳层电子结构使得猝灭截面增大,而转动态 态传能截面减小.     

H+HF(v,j)→H+HF(v′,j′)的传能动力学理论研究

本文运用非含时量子动力学方法研究了H+HF(v=1,j)→H+HF(v'=0,j')传能过程在295~500 K的振动弛豫速率常数.在此温度范围内,所有转动分辨的振动弛豫速率常数随着温度升高而单调递增,速率常数最大的末态转动量子数随着初态转动量子数的增加而增加.在室温下,振动态分辨的振动弛豫速率常数与实验值符合较好.同时,我们也计算了H+HF(v=1,j)→H+HF(v'=1,j')纯转动传能过程在500 K的速率常数,发现它们整体上比振动弛豫速率常数大了几个数量级,并且△j=-1的速率常数一般大于△j=-1的速率常数.     

He(2^3S)与CH3I和CH3Br在流动余辉中传能的解离激发反应

本文利用流动余辉技术研究了亚稳态He(2^3S)与CH3I和CH3Br传能时分子的解离激发过程。实验中测定了产物的相对分布、CH(A, v'=0)的转动布居和主要碎片的形成速率常数。     

He(2^3S)与CH3I和CH3Br在流动余辉中传能的解离激发反应

本文利用流动余辉技术研究了亚稳态He(2^3S)与CH3I和CH3Br传能时分子的解离激发过程。实验中测定了产物的相对分布、CH(A, v'=0)的转动布居和主要碎片的形成速率常数。     

He(2~3S)与含氢卤代甲烷传能反应中产生的CH(A~2Δ,ν′=0)的新生态转动分布

流动余辉技术在基元反应动力学研究中已得到了广泛应用。当亚稳态稀有气体原子与某些分子发生传能反应时,母体分子解离产生一些较小的激发态碎片。通过测量碎片的发射光谱可以获得产物内能分布以及解离过程的动力学信息。使用该技术,Someda和Roychowdhury分别研究了He(2~3S)与NH_3和PF_3的反应,获得了NH(A,C)和PF(A)的内能分布规律,并讨论了解离反应的机理。     

转动传能中NH2(~A)精细结构态变化的研究

利用高分辨光谱技术观察了NH2(~2A A,090)423(F1/F2)在单次碰撞条件下的精细态色散荧光光谱,发现NH2(~2A A1)在与闭壳层分子碰撞传能过程中,母能级的自旋-转动耦合守恒,从实验上直接证实了在开壳层-闭壳层分子碰撞过程中电子自旋为一旁观者的假设;由于长程作用力造成子能级具有保持原来自旋-转动耦合的倾向.     

二极管激光探测法研究高振动NO2与NH3振动传能

用高分辨、高速、高灵敏度的二极管激光探测法研究了高振动激发的NO2分子与NH3分子的振动能量转移，YAG532um倍频光作为NO2的激发光源，红外二极管激光（约10μ）探测NH3ν2模被激发振转能级的时间分辨的吸收光谱.实验得到NO2与NH3气压比为1：5，1：1，2：1和5：1时NH3（0100；7；k）的激发速率分别为9．28、6．42、5．05和3．65×10－1ms－1·Pa－1.在NH3压力为133Pa时，有大约6％的高振动激发NO2能量转移到NH3ν2振动模，其它大部分转移到NH3的转动和平动能．文中讨论了振动激发的机理．     

NH2(A~2A1, 090,423)的电子猝灭和转动态-态传能

在束-气和束-束实验条件下,详细研究了NH2(A2A1,090,423)自由基分别与Ar,N2,O2和NH3碰撞引起的电子态猝灭和转动态-态传能,获得了总的猝灭截面σQ(分别为≤0.17、0.26、0.30和0.48 nm2),以及相对转动态-态传能截面.利用碰撞络合物模型计算的电子猝灭截面与实验测得的截面具有基本相同的趋势,表明长程吸引势在猝灭过程中起着重要的作用.同时还发现,转动态-态传能中相对截面随着碰撞对的折合质量的减小而下降.由于NH3具有较大的偶极矩以及O2的开壳层电子结构使得猝灭截面增大,而转动态-态传能截面减小.     

单次碰撞条件下NH2(A2A1,(0,9,0))转动非弹性碰撞

在单次碰撞条件下 ,对NH2 (～A2 A1,(0 ,9,0 ) )的转动非弹性碰撞进行了详细的研究 ,包括不同转动能级、核自旋、及自旋分裂双重态的传能 ,直接得到了一些倾向性规则 ,并且对于能隙规律和角动量传递规律在其中的重要性作了初步探讨     

NH4VO3在NH4H2PO4-H2O和(NH4)3PO4-H2O体系中的溶解度

采用等温溶解法测定了偏钒酸铵(NH₄VO₃)在NH₄H₂PO₄-H₂O和(NH₄)₃PO₄-H₂O体系中T = 298.15-328.15 K时的溶解度以及溶液的密度和pH值。结果表明, NH₄VO₃的溶解度随着(NH₄)₃PO₄或NH₄H₂PO₄溶液浓度的增大,先降低后升高,这是由于同离子效应、化学反应平衡及离子活度的共同作用。比较T = 298.15K时, NH₄VO₃分别在NH₄H₂PO₄-H₂O、(NH₄)₂HPO₄-H₂O和(NH₄)₃PO₄-H₂O体系中溶解度,发现在相同的磷酸盐浓度下, NH₄VO₃的溶解度在NH₄H₂PO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在(NH₄)₂HPO₄-H₂O体系中最小。进一步地,在T = 298.15 K和磷酸盐浓度C = 0.5 mol·kg^-1时,结合pH值和反应溶度积常数K_SP等计算三个体系中的平均离子活度系数(γ_±),发现γ_±值在(NH₄)₂HPO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在NH₄H₂PO₄-H₂O体系中最小,与溶解度规律一致。     

Ab initio thermal rate coefficients for H + NH3 ⇌ H2 + NH2

The reversible reaction NH₃ + H ⇌ H₂ + NH₂, which plays an important role in NH₃ fuel combustion, is studied with a theoretical approach that combines the high-accuracy extrapolated ab initio thermochemistry (HEAT) protocol with semiclassical transition state theory (SCTST). The calculated forward reaction is endothermic by 11.8 ± 1 kJ/mol, in nearly perfect agreement with the active thermochemical tables (ATcT) value of 11.5 ± 0.2 kJ/mol. Using this improved thermochemistry yields better rate constants, especially at low temperatures. Experimental rate constants available from 400 to 2000 K for the forward and reverse reaction pathways can be reproduced (within 20%) by the calculations from first principles.     

Isotype Strukturen einiger Hexaamminmetall(II)-halogenide von 3d-Metallen: [V(NH3)6]I2, [Cr(NH3)6]I2, [Mn(NH3)6]Cl2, [Fe(NH3)6]Cl2, [Fe(NH3)6]Br2, [Co(NH3)6]Br2 und [Ni(NH3)6]Cl2

The Structures of some Hexaammine Metal(II) Halides of 3 d Metals: [V(NH₃)₆]I₂, [Cr(NH₃)₆]I₂, [Mn(NH₃)₆]Cl₂, [Fe(NH₃)₆]Cl₂, [Fe(NH₃)₆]Br₂, [Co(NH₃)₆]Br₂ and [Ni(NH₃)₆]Cl₂ Crystals of yellow [V(NH₃)₆]I₂ and green [Cr(NH₃)₆]I₂ were obtained by the reaction of VI₂ and CrI₂ with liquid ammonia at room temperature. Colourless crystals of [Mn(NH₃)₆]Cl₂ were obtained from Mn and NH₄Cl in supercritical ammonia. Colourless transparent crystals of [Fe(NH₃)₆]Cl₂ and [Fe(NH₃)₆]Br₂ were obtained by the reaction of FeCl₂ and FeBr₂ with supercritical ammonia at 400°C. Under the same conditions orange crystals of [Co(NH₃)₆]Br₂ were obtained from [Co₂(NH₂)₃(NH₃)₆]Br₃. Purple crystals of [Ni(NH₃)₆]Cl₂ were obtained by the reaction of NiCl₂ · 6H₂O and NH₄Cl with aqueous NH₃ solution. The structures of the isotypic compounds (Fm3 m, Z = 4) were determined from single crystal diffractometer data (see “Inhaltsübersicht”). All compounds crystallize in the K₂[PtCl₆] structure type. In these compounds the metal ions have high-spin configuration. The orientation of the dynamically disordered hydrogen atoms of the ammonia ligands is discussed.     

以ZrO2-TiO2为载体的整体式锰基催化剂应用于低温NH3-SCR反应

以MnO2为活性组分,Fe2O3为助剂,制备了以TiO2及ZrO2-TiO2为载体的整体式催化剂.考察了它们在不同温度焙烧后应用于富氧条件下,NH3选择性催化还原.(NH3-SCR)氮氧化物的低温反应性能和高温稳定性.用X射线衍射(XRD)实验、比表面积测定(BET)、储氧性能测定(OSC)及程序升温还原(H2-TPR)等方法对催化剂进行了表征.结果表明,以ZrO2-TiO2为载体的催化剂具有很好的高温热稳定性,并具有较高的比表面积和储氧能力.同时具有较强的氧化能力.催化剂的活性测试结果表明,以ZrO2-TiO2为载体的整体式锰基催化剂明显地提高了NH3-SCR反应的低温活性,具有良好的应用前景.     

用离散-连续模型计算NH2-,NH3和NH4+的溶剂化自由能

通过理论计算推测NH2-,NH3和NH4+在水溶液第一溶剂化层中与之直接作用的水分子分别为2,4和4个,并采用离散-连续模型计算了NH2-,NH3,NH3和NH4+在水溶液中的溶剂化自由能.结果表明,由于离散-连续模型在从头算水平考虑了溶质分子与第一溶剂化层溶剂分子之间的作用,能更准确地描述溶剂化作用.此外,采用更加符合溶液中真实情况的溶剂化构型,能得到更准确的溶剂化性质.     

Electrocatalysis of N2 to NH3 by HKUST‐1 with High NH3 Yield

Electrolytic ammonia synthesis from nitrogen at ambient conditions is appearing as a promising alternative to the Haber‐Bosch process which is consuming high energy and emitting CO₂. Here, a typical MOF material, HKUST‐1 (Cu?BTC, BTC=benzene‐1,3,5‐tricarboxylate), was selected as an electrocatalyst for the reaction of converting N₂ to NH₃ under ambient conditions. At ?0.75 V vs. reversible hydrogen electrode, it achieves excellent catalytic performance in the electrochemical synthesis of ammonia with high NH₃ yield (46.63 μg h^?1 mg^?1 _cat. or 4.66 μg h^?1 cm^?2) and good Faraday efficiency (2.45%). It is indicated that the good performance of the HKUST‐1 catalyst may originate from the formation of Cu(I). In addition, the catalyst also has good selectivity for N₂ to NH₃.     

NH2(～X2B1)与CH4反应机理的理论研究

在密度泛函理论B3LYP／6－311G^*水平下，研究了NH2与CH4的反应机理。通过振动频率和内禀反应坐标（IRC）分析，对反应过渡态进行了确认。在QCISD（T）／6－311G^*水平下进行了单点能计算，并进行了零点能校正，结果表明，反应NH2＋CH4→N3＋CH3是主要的反应通道。     

Darstellung und Struktur von Sn(NH2)2F2

Synthesis and Structure of Sn(NH₂)₂F₂ Diamido-difluoro-tin Sn(NH₂)₂F₂ can be produced by ammonolysis from (NH₄)₂SnF₆ at 613 K. The compound is a product from Sn(NH₃)₂F₄ formed during the ammonolysis reaction. Sn(NH₂)₂F₂ crystallizes in space group C2/m (No. 12) with lattice constants a = 1070.18(7), b = 325.38(3) pm, c = 505.02(3) pm and β = 105.728(3)° (V = 169.271(6) · 10⁶ pm³) containing two formula units per unit cell. Data refinement by the Rietveld method yields a Bragg R-value of R_Bragg = 0.0514 (Profile R-value R_wp = 0.177). Tin is octahedrally coordinated by two fluorine atoms and for amido groups. The octahedra are connected to one-dimensional strings by edge sharing. The NH₂ groups are in the bridging position whilst the fluorine atoms are terminal.     

Die Ammonolyse von (NH4)2GeF6. Darstellung und Struktur von NH4[Ge(NH3)F5]

Ammonolysis Reaction of (NH₄)₂GeF₆. Synthesis and Structure of NH₄[Ge(NH₃)F₅] (NH₄)₂GeF₆ reacts with ammonia to yield NH₄[Ge(NH₃)F₅] at 280°C. The reaction path was elucidated by in situ time and temperature resolved X-ray powder diffraction. NH₄[Ge(NH₃)F₅] crystallizes isostructurally to NH₄[Si(NH₃)F₅] in the tetragonal space group P4/n (No. 85) with lattice constants a = 619.41(1) pm and c = 724.70(1) pm. The germanium atom is coordinated by five fluorine atoms and the nitrogen atom of the ammonia molecule. The ammonium cation is located on the Wyckoff position (2 a) in P4/n. The crystal structure is stabilized by extensive hydrogen bonding.     

Interaction between NH2NO and H2O2: A quantum chemistry study

The H‐bonded complexes formed from interaction between NH₂NO (NA) and H₂O₂ (HP) have been investigated by using B3LYP and MP2 methods with a wide range of basis sets. We found six H‐bonded complexes in which three of them have cyclic structure. Calculations carried out at various levels show that the seven‐membered cyclic structure with O···HO and O···HN hydrogen bonding interactions is the most stable complex. The large binding energy obtained for A1 complex probably results from a more linear arrangement of the O···H N and O H···OH‐bonds in the seven‐membered structure A1. The natural bond orbital (NBO) analysis and the Bader's quantum theory of atoms in molecules have been used to elucidate the interaction characteristics of the NA‐HP complexes. The NBO results reveal that the charge transfer energy corresponds to the H‐bond interactions for A1 complex is grater than other complexes. The electrostatic nature of H‐bond interactions is predicted from QTAIM analysis. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010