Determination of N and O – Atom and N2(A) Metastable Molecule Densities in the Afterglows of N2 and N2‐O2 Microwave Discharges

Early afterglows of N₂ and N₂‐O₂ flowing microwave discharges are characterized by optical emission spectroscopy. The N and O atom and N₂(A) metastable molecule densities are determined by optical emission spectroscopy after calibration by NO titration for N‐atoms and measurements of NO and N₂ band intensities for O‐atoms and N₂(A) metastable molecules. By using N₂ tanks with 50 and 10 ppm impurity, it is determined in the afterglow an O‐ atom impurity of 150‐200 ppm. Variations of the N and O‐atom and N₂(A) metastable molecule densities are obtained in the early afterglow of N₂–(9·10^–5–3·10^–3)O₂ gas mixtures. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Determination of N and O‐atoms and N2 (A) Metastable Molecule Densities in the Afterglows of N2‐H2, Ar‐N2‐H2 and Ar‐N2‐O2 Microwave Discharges

Early afterglows of N₂‐H₂, Ar‐N₂‐H₂ and Ar‐N₂‐O₂ flowing microwave discharges are characterized by optical emission spectroscopy. The N and O atoms and the N₂ (A) metastable molecule densities are determined by optical emission spectroscopy after calibration by NO titration for N and O‐atoms and measurements of NO and N₂ band intensities. If an uncertainty of 30% is estimated on N‐atomic density, an inaccuracy of one order of magnitude is obtained on the O and N₂ (A) densities. In N₂‐(0.05‐2.5%)H₂ and Ar‐(1‐50%)N₂‐(0.05‐2.5%) H₂ gas mixtures, the O‐atoms are coming from O₂ impurities in the discharge. Concentrations of N and O‐atoms and of N₂ (A) densities are compared to the ones obtained in Ar‐(5‐50%)N₂‐(0.2‐2.5%) O₂ gas mixtures in which a controlled amount of O₂ is added. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

(C_5H_(11)N_2)~+和(C_7H_(12)N_2)~(2+)的NMR研究

结合1H NMR,13C NMR谱,分别对钨、钼配合物{WO2(C10H6O2)2(C5H11N2)2[H2N(CH2)3NH2]}3(1),{(C5H11N2)2[H2N(CH2)3NH2][MoO2(C10H6O2)2]}(2),{(C7H12N2)2[MoO2(C10H8O2)2]}(3)晶体结构中小分子环进行了归属.其中,配合物1和2中(C5H11N2)+的NMR研究证实了六元环由1,3-丙二胺和乙腈化合而成,配合物3中(C7H12N2)2+的NMR谱图证实了七元环由乙二胺和乙酰丙酮化合而成,并且推导出这些亲核加成-消除反应的反应机理.配合物1~3中的小分子环的合成在其它体系中尚未见报导,而在合成它们的反应中作为新产物随主体晶体析出,并由晶体结构解析和NMR得到了证实.     

Radiative Transitions and Temperature Time Dependences in Pulse Excited Microwave Discharges – (N2, Ar + N2)

Quantitative spectral and microwave measurements of vibrational temperatures and electron densities were performed for 2400 MHz non-isothermic pulse excited discharges in flowing nitrogen and argon at pressures (60–2700) Pa. A detailed analysis of the N₂ vibrational states population for the N₂ C³Π_u, X¹Σ_g⁺ electronic states has been carried out. The basic difficulties encountered when comparing the spectroscopically determined values of vibrational temperatures with corresponding quantities of the ground electronics state are mentioned and the time resolved dependences of the translational gas temperature in N₂ during the microwave pulse is evaluated. The steady state in the nitrogen pulse excited microwave plasma is reached within 3 · 10^?4 s, but generally, this time depends on the gas pressure in the discharge tube. In the Ar + N₂ mixtures the excitation conditions are complicated by the metastable argon atoms (3P_2,0) creating the nonequilibrium populations of electronic, vibrational and rotational N₂ states.     

气相中2Ca＋介入N2O与CO, N2O与H2反应的计算研究

本文采用密度泛函理论DFT-UB3LYP方法, 在6-311+G(2d, p)的基组下, 计算研究了气相中Ca+离子介入N2O (1∑+)和CO (1∑+) 与N2O (1∑+) 和 H2 (1∑+g)反应的微观机理. 报道了二重态势能面上各反应物、中间体和过渡态的构型特征及能量, 并用频率分析和内禀反应坐标（IRC）方法对过渡态进行了验证. 计算结果表明,金属离子参与N2O和CO与N2O和H2的反应都分两步进行, 其中Ca+离子对反应N2O (X1∑+) + CO (1∑+)生成N2 (X1∑+g) + CO2 (1∑+g)比较Fe+, Ir+, Pt+等的金属离子有良好的催化作用, 而对反应N2O (X1∑+) + H2 (1∑+g) → N2 (1∑+g) + H2O (1A1) 催化作用不是很好,N2、CaOH+和H是该反应的主要产物,与实验观测结果相符, 并通过对金属离子亲氧性（OA）的计算, 从热力学方面进一步说明主题反应的可行性.     

气相中2Ca＋介入N2O与CO, N2O与H2反应的计算研究

本文采用密度泛函理论DFT-UB3LYP方法, 在6-311+G(2d, p)的基组下, 计算研究了气相中Ca+离子介入N2O (1∑+)和CO (1∑+) 与N2O (1∑+) 和 H2 (1∑+g)反应的微观机理. 报道了二重态势能面上各反应物、中间体和过渡态的构型特征及能量, 并用频率分析和内禀反应坐标（IRC）方法对过渡态进行了验证. 计算结果表明,金属离子参与N2O和CO与N2O和H2的反应都分两步进行, 其中Ca+离子对反应N2O (X1∑+) + CO (1∑+)生成N2 (X1∑+g) + CO2 (1∑+g)比较Fe+, Ir+, Pt+等的金属离子有良好的催化作用, 而对反应N2O (X1∑+) + H2 (1∑+g) → N2 (1∑+g) + H2O (1A1) 催化作用不是很好,N2、CaOH+和H是该反应的主要产物,与实验观测结果相符, 并通过对金属离子亲氧性（OA）的计算, 从热力学方面进一步说明主题反应的可行性.     

Ni(C3H10N2)2NO2(ClO4)晶体的ESR研究

报道了Ni(C₃H₁₀N₂)₂NO₂(ClO₄)晶体在T=1.5K温度和W波段的ESR实验.建立了d⁸离子基态³A₂(F)的零场分裂参量D,E,和g因子与斜方对称晶场势参量间的关系,并应用于Ni(C₃H₁₀N₂)₂NO₂(ClO₄)晶体.计算值与实验数据符合很好,表明所给关系式是合理的.     

N2（A）及N（2D）对IF（X）的传能研究

在微波放电系统中,对NH_3-F-F_2-CF_3I体系进行研究,结果表明,向IF(X)传能的诸多媒介中,N_2(A)及N(~2D)起着主要作用,并且这一结论在经微波激发后的N_2与CF_3I的直接反应中得到了进一步证实。     

气相中2Sr+,2Ba+介入N2O与H2反应的理论研究

运用密度泛函理论DFT-UB3LYP方法,对2Sr+、2Ba+采用相对论校正赝势基组SDD,对N、O、H采用6-311+G(2d,p)基组,计算研究了气相中碱土金属离子2Sr+、2Ba+介入N2O(1∑+)和H2(1∑g+)反应的微观机理,优化了二重态势能面上各反应物、中间体和过渡态的构型特征,用频率分析方法和内禀反应坐标方法(IRC)对过渡态进行了验证.运用Kozuch撰写的能量跨度模型(Energetic Span Model,δlE),确定了决定循环反应速率的决速过渡态(TDTS)和决速中间体(TDI),并利用转化频率(Turnover Frequency,TOF)评估了催化性能.结果表明:从热力学性质分析2Sr+、2Ba+离子对N2O(1∑+)和H2(1∑+g)反应很好的催化作用,可得到目标产物N2(1∑g+)和H2O(1 A1),却从动力学性质分析主要反应产物为N2、SrOH+ (BaOH+)和H,最终动力学因素在反应中起决定性作用,以上结论与实验观测结果相符.     

气相中2Sr＋, 2Ba＋介入N2O与H2反应的理论研究

本文运用密度泛函理论DFT-UB3LYP方法, 对2Sr+、2Ba+采用相对论校正赝势基组SDD, 对N、O、H采用6-311+G(2d,p)基组, 计算研究了气相中碱土金属离子2Sr+、2Ba+介入N2O (1∑+) 和 H2 (1∑+g)反应的微观机理, 优化了二重态势能面上各反应物、中间体和过渡态的构型特征, 用频率分析方法和内禀反应坐标方法(IRC)对过渡态进行了验证. 运用Kozuch撰写的能量跨度模型(Energetic Span Model, δE),确定了决定循环反应速率的决速过渡态(TDTS)和决速中间体(TDI), 并利用转化频率(Turnover Frequency,TOF)评估了催化性能. 结果表明：从热力学性质分析2Sr+、2Ba+离子对N2O (1∑+) 和 H2 (1∑+g)反应很好的催化作用,可得到目标产物N2 (1∑+g) 和 H2O (1A1), 却从动力学性质分析主要反应产物为N2、SrOH+ (BaOH+)和H, 最终动力学因素在主题反应中起决定性作用,以上结论与实验观测结果相符.     

Cs(6P)激发态的辐射及与N2碰撞的能量转移

应用激光吸收和荧光方法,测量了Cs(6P)态与N2碰撞的精细结构转移和碰撞猝灭截面。Cs原子被激光激发到6P3/2态,将与泵浦激光束反向平行的检测激光束调到6PJ→8S1/2的跃迁,测量了6PJ激发态的密度及空间分布,由此计算了6PJ→6S的有效辐射率。在T=337 K(蒸气压公式给出Cs密度N0=1.25×1012cm-3)和N2密度2×1016相似文献   

Zeeman relaxation of N2 + (2Σ+) in collisions with 3He and 4He

We compare the cross sections for the transitions changing the projection of the total angular momentum of N₂ ⁺(²Σ) in collisions with ³He and ⁴He at very low collision energy. The fundamental states of the two nuclear spin isomers of N₂ ⁺ are considered as well as the two fine structure levels of the first excited para level N=2. It is shown that the two fundamental states of the two nuclear spin isomers behave differently. For the fundamental para level N=0 of N₂ ⁺, the projection changing cross section is always negligible compared to the elastic one for both He isotopes. For the fundamental ortho level N=1 of N₂ ⁺, the spin-rotation interaction couples the different spin levels directly so the spin relaxation becomes a first order process. The associated resonances increase the projection changing cross section which remains smaller but becomes comparable with the elastic one. This is in contrast with the excited rotational levels of N₂ ⁺, which for the rotational deactivation and elastic channels are found to be equal around the resonances for the collisions involving ³He. These two channels are always larger than the projection changing one. We also find that, for transitions involving the fundamental rotational state, the domain of validity of the threshold laws discussed by Krems and Dalgarno [Phys. Rev. A 67, 050704 (2003)] for a potential decreasing faster than 1/r2 is shortened, due to the long range charge induced dipole potential. This effect is illustrated for the collisions of ³He with the fundamental para state of N₂ ⁺.     

Synthesis and vibrational analysis of N‐(2′‐Furyl)‐Imidazole

The N‐(2′‐furyl)‐imidazole ( 1 ) has been prepared and characterized using infrared, Raman and multidimensional nuclear magnetic resonance spectroscopies. Theoretical calculations have been carried out by employing the Density Functional Theory (DFT) method, in order to optimize the geometry of their two conformers in the gas phase and to support the assignments of the vibrational bands of 1 to their normal modes. For a complete assignment of the compound, DFT calculations were combined with Scaled Quamtum Mecanic Force Field (SQMFF) methodology in order to fit the theoretical wavenumber values to the experimental one. Furthermore, Natural Bond Orbital (NBO) and topological properties by Atoms In Molecules (AIM) calculations were performed to analyze the nature and magnitude of the intramolecular interactions. The result reveals that two conformers are expected in liquid phase. Copyright © 2009 John Wiley & Sons, Ltd.     

Structural and vibrational analyses of 2‐(2‐benzofuranyl)‐2‐imidazoline

We have studied 2‐(2‐benzofuranyl)‐2‐imidazoline (BFI) and characterized it by using infrared and Raman spectroscopies. The density functional theory (DFT) method together with Pople's basis set shows that two conformers exist for the title molecule as have been theoretically determined in the gas phase and that, probably, an average of both conformations is present in the solid phase. The harmonic vibrational wavenumbers for the optimized geometry of the latter conformer were calculated at the B3LYP/6‐31G* level in the proximity of the isolated molecule. For a complete assignment of the IR and Raman spectra in the compound in the solid phase, DFT calculations were combined with Pulay's scaled quantum mechanics force field (SQMFF) methodology in order to fit the theoretical wavenumbers to the experimental ones. Copyright © 2010 John Wiley & Sons, Ltd.     

A comparative nearside-farside analysis of the He–N2 + and He–N2 inelastic collisions

A comparative study of the inelastic scattering of ¹⁴N₂ ⁺ and ¹⁴N₂ in collision with ³He atoms is presented. The unrestricted nearside-farside (NF) method proposed by Connor [J. Chem. Phys. 104, 2297 (1995)] is applied to analyse the Close Coupling rotationally state selected angular distributions for four kinetic energies. These four energies illustrate different regimes of the dynamics. The relationships between the structures of the calculated differential cross-sections (DCS) and the different regions of the potential energy surfaces involved which can be extracted from semi classical models are here easily obtained from a simple reading of the (NF) figures. At the higher energy far-off the wells (1000 cm^-1) the shape of the DCS are quite similar for the two systems and their nearside-farside components also, showing that the inelastic process is controlled by the short range repulsive part of the potential which is essentially the same for these two collisions. When the energy is decreased the differences between the two wells associated with the He–N₂ ⁺ and He–N₂ complexes are responsible for the differences between the DCS for the two systems. The farside component associated with the well become more and more prominent for the elastic scattering while inelastic scattering remains controlled by the repulsive core in a large angular interval. The nearside farside analysis gives also a new picture of a resonance which is regarded as an equilibrium between the repulsive and the attractive parts of the potential.     

Solvent‐dependent structural dynamics of 2(1H)‐pyridinone in light absorbing S4(ππ*) state

The B‐band resonance Raman spectra of 2(1H)‐pyridinone (NHP) in water and acetonitrile were obtained, and their intensity patterns were found to be significantly different. To explore the underlying excited state tautomeric reaction mechanisms of NHP in water and acetonitrile, the vibrational analysis was carried out for NHP, 2(1D)‐pyridinone (NDP), NHP–(H₂O)_n (n = 1, 2) clusters, and NDP–(D₂O)_n (n = 1, 2) clusters on the basis of the FT‐Raman experiments, the B3LYP/6‐311++G(d,p) computations using PCM solvent model, and the normal mode analysis. Good agreements between experimental and theoretically predicted frequencies and intensities in different surrounding environments enabled reliable assignments of Raman bands in both the FT‐Raman and the resonance Raman spectra. The results indicated that most of the B‐band resonance Raman spectra in H₂O was assignable to the fundamental, overtones, and combination bands of about ten vibration modes of ring‐type NHP–(H₂O)₂ cluster, while most of the B‐band resonance Raman spectra in CH₃CN was assigned to the fundamental, overtones, and combination bands of about eight vibration modes of linear‐type NHP–CH₃CN. The solvent effect of the excited state enol‐keto tautomeric reaction mechanisms was explored on the basis of the significant difference in the short‐time structural dynamics of NHP in H₂O and CH₃CN. The inter‐molecular and intra‐molecular ESPT reaction mechanisms were proposed respectively to explain the Franck–Condon region structural dynamics of NHP in H₂O and CH₃CN.Copyright © 2015 John Wiley & Sons, Ltd.     

H2-O2(N2)混气着火过程非线性特性研究

本文采用基元反应模拟H2-O2(N2)混合气体的着火过程,得到了不同散热和不同燃料-氧化剂初始浓度比条件下着火临界曲线。结果表明: H2/O2摩尔比相同时,不同散热条件下的着火临界曲线非常相似,可近似看成同一曲线在第二区的“延伸线”上滑移。临界曲线第二区的P—T关系符合2k1=ks[Ms]。散热对着火极限的影响和着火延迟时间有密切关系,在临界曲线第二区延迟时间最小,导致散热对该区的影响最弱,从而使着火临界曲线非常相似。     

Vibrational spectra of rhombohedral TeO3 compared to those of ReO3‐like proto‐phase and α‐TeO2 (paratellurite): lattice dynamic and crystal chemistry aspects

Vibrational spectra of rhombohedral TeO₃ (r‐TeO₃) are analyzed along with those of ReO₃‐like proto‐phase (c‐TeO₃) and α‐TeO₂ (paratellurite), emphasizing their lattice dynamic and crystal chemistry aspects. It is shown that (1) r‐TeO₃ can be regarded as resulting from the condensation of a particular R‐point soft phonon of c‐TeO₃; (2) the Raman spectra of r‐TeO₃ and α‐TeO₂ are indicative of the two fundamentally different (from the crystal chemistry point of view) types of crystalline oxides, namely, framework‐type and island‐type, respectively. Copyright © 2010 John Wiley & Sons, Ltd.     

(p,n)和(p,2n)反应激发函数的系统学研究

从普朗克(Planck)黑体辐射公式和实验测量数据出发,采用唯象的方法提出了包含两个可调参量,入射质子能量从阈能到150MeV,靶核质量数在44相似文献   

苯胺分子S_1态振动光谱及ab initio计算(英文)

利用紫外激光,结合超声速脉冲分子技术和飞行时间质谱仪,在287～296 nm波长范围内实验研究了苯胺分子的共振双光子电离光谱(R2PI).实验中观测到对应S_1←S_0跃迁的0-0带出现在293.86nm(3.4029 cm~(-1))处,并测得对应S_1态的若干振动模和来自S_0态的热带.为了对S_1态的振动模进行标定,分别在HF/6-31+G(d,p)和CIS/6-31+G(d,p)基组水平上对苯胺在S_0态的构型进行优化和在S_1态对其振动频率进行分析计算.另外,利用自然键轨道分析(NBO)讨论了电子激发过程.结果显示,来自氨基氮原子上的一个电子从对应的孤对电子轨道激发到苯环的π反键轨道上,恰好对应的是S_1←S_0跃迁.