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1.
Ohne Zusammenfassung 相似文献
2.
The results of several MC SCF calculations on CH 4, C 2H 4 and C 2H 6 with minimun bases of Slater type AO's are reported. The computing method is a quadratically convergent process. Better final energies are obtained if localized MO's are used. 相似文献
3.
Zur Trennung von H2, O2, N2, NO, CO, N2O, CO2, C2H6, C2H4, C2H2, NO2(N2O4) und Feuchtigkeit
Ohne Zusammenfassung 相似文献
4.
An experimental study on the conversion of NO in the NO/N 2, NO/O 2/N 2, NO/C 2H 4/N 2 and NO/C 2H 4/O 2/N 2 systems has been carried out using dielectric barrier discharge (DBD) plasmas at atmospheric pressure. In the NO/N 2 system, NO decomposition to N 2 and O 2 is the dominating reaction; NO conversion to NO 2 is less significant. O 2 produced from NO decomposition was detected by an on-line mass spectrometer. With the increase of NO initial concentration, the concentration of O 2 produced decreases at 298 K, but slightly increases at 523 K. In the NO/O 2/N 2 system, NO is mainly oxidized to NO 2, but NO conversion becomes very low at 523 K and over 1.6% of O 2. In the NO/C 2H 4/N 2 system, NO is reduced to N 2 with about the same NO conversion as that in the NO/N 2 system but without NO 2 formation. In the NO/C 2H 4/O 2/N 2 system, the oxidation of NO to NO 2 is dramatically promoted. At 523 K, with the increase of the energy density, NO conversion increases rapidly first, and then almost stabilizes at 93–91% of NO conversion with 61–55% of NO 2 selectivity in the energy density range of 317–550 J L −1. It finally decreases gradually at high energy density. A negligible amount of N 2O is formed in the above four systems. Of the four systems studied, NO conversion and NO 2 selectivity of the NO/C 2H 4/O 2/N 2 system are the highest, and NO/O 2/C 2H 4/N 2 system has the lowest electrical energy consumption per NO molecule converted. 相似文献
5.
Experimental differential cross sections for 40 keV electrons scattered by C 2H 2, C 2H 4 and C 2H 6 molecules were measured using the gas electron diffraction method in the range of the scattering variable s from s = 1 A ?1 to s = 30 A ?1. The differential cross sections for neon were also measured and compared with calculated differential cross sections to calibrate the diffractograph. Experimental differential cross sections show significant deviations with respect to theoretical differential cross sections calculated from the Debye-Ehrenfest model, mainly in the range of small scattering angles. The observed differences are connected to chemical binding effects. From the experimental data, an estimation of the binding energy was carried out. The deduced values: ?0.58 ± 0.20 au for C 2H 2, ?0.94 ± 0.30 au for C 2H 4 and ?1.23 ± 0.40 au for C 2H 6 are in agreement with those obtained by thermochemical methods. 相似文献
6.
C 2(a 3π u) disappearance rate constants of 1.44, 0.96, 0.0296, 0.0130 and < 10 ?6(x10 ?10cm 3s ?1) are reported for reactions with C 2H 4, C 2H 2, O 2, C 2H 6, and CH 4, respectively at 298 K. C 2(a 3π u) fragments are generated by multiphoton ArF excimer laser photodissociation at C 2H 2, and monitored by dye laser induced fluorescence. Arguments are presented which favor chemical reactions over the C 2(a 3π u) → (X 1σ +g) quenching channel. C 2 + C 2H 2 represents the one possible exception to the reactive channel. 相似文献
7.
The high-pressure limiting rate constants of the reactions between H or D atoms and three isotopic ethylenes have been measured in the temperature range 206–461 K. Practically no isotope effects due to the differences between the ethylenes could be observed. This result does not agree with the prediction recently made by the activated complex theory. 相似文献
8.
LnCl 3 (Ln=Nd, Gd) reacts with C 5H 9C 5H 4Na (or K 2C 8H 8) in THF (C 5H 9C 5H 4 = cyclopentylcyclopentadienyl) in the ratio of 1 : to give (C 5H 9C 5H 4)LnCl 2(THF) n (orC 8H 8)LnCl 2(THF) n], which further reacts with K 2C 8H 8 (or C 5H 9C 5H 4Na) in THF to form the litle complexes. If Ln=Nd the complex (C 8H 8)Nd(C 5H 9C 5H 4)(THF) 2 (a) was obtained: when Ln=Gd the 1 : 1 complex [(C 8H 8)Gd(C %H 9)(THF)][(C 8H 8)Gd(C 5H 9H 4)(THF) 2] (b) was obtained in crystalline form. The crystal structure analysis shows that in (C8H8)Ln(C5H9C5H4)(THF)2 (Ln=Nd or Gd), the Cyclopentylcyclopentadieny (η5), cyclooctatetraenyl (η8) and two oxygen atoms from THF are coordinated to Nd3+ (or Gd3+) with coordination number 10. The centroid of the cyclopentadienyl ring (Cp′) in C5H9C5H4 group, cyclooctatetraenyl centroid (COTL) and two oxygens (THF) form a twisted tetrahedron around Nd3+ (or Gd3+). In (C8H8)Gd(C5H9C5H4)(THF), the cyclopentyl-cyclopentadienyl (η5), cyclooctatetraenyl (η8) and one oxygen atom are coordinated to Gd3+ with the coordination number of 9 and Cp′, COT and oxygen atom form a triangular plane around Gd3+, which is almost in the plane (dev. -0.0144 Å). 相似文献
9.
The infrared and Raman spectra of C 4H 8CHCOOH, C 4H 8CHCOOD, C 4H 8CDCOOH, C 4H 8CDCOOD and their sodium salts were studied and frequency assignments made; the ring puckering vibrations were observed in the Raman spectrum. The depolarisation values show the existence of a plane of symmetry, perpendicular to the ring compatible with a “bent” structure. 相似文献
10.
The reactions of methane with the dications C 7H 62+, C 7H 72+, and C 7H 82+ generated by electron ionization of toluene are studied using mass-spectrometry tools. It is shown that the reactivity is dominated by the formation of doubly charged intermediates, which can either eliminate molecular hydrogen to yield doubly charged products or undergo charge-separation reactions leading to the formation of a methyl cation and the corresponding C 7H n+1+ monocation. Typical processes observed for dications, like electron transfer or proton transfer, are largely suppressed. The theoretically derived mechanism of the reaction between C 7H 62+ and CH 4 indicates that the formation of the doubly charged intermediate is kinetically preferred at low internal energies of the reactants. In agreement, the experimental results show a pronounced hydrogen scrambling and dominant formation of the doubly charged products at low collision energies, whereas direct hydride transfer prevails at larger collision energies. 相似文献
11.
The electronic and thermal energy differences, Δ E(t-s); enthalpy differences, Δ H(t-s); and free energy differences between the singlet and triplet states, Δ G(t-s), were calculated for C 6H 6C, C 6H 6Si, C 6H 6Ge, C 6H 6Sn, and C 6H 6Pb at the B3LYP/6-311++G (3 df, 2 p) level. The singlet-triplet splitting, G
s-t, of C 6H 6C, C 6H 6Si, C 6H 6Ge, C 6H 6Sn, and C 6H 6Pb generally increased from C 6H 6C toward C 6H 6Pb. The most stable tautomers and conformers were suggested for the singlet and triplet states of C 6H 6M (M = C, Si, Ge, Sn and Pb). The geometrical parameters were calculated and discussed.
The text was submitted by the authors in English. 相似文献
12.
用三原子模型的准经典轨线方法研究了Cl与C2H6(v=0,j)的反应。计算结果表明,反应产物HCl的角度分布基本上为各向同性,其振动分布处于基态,与实验结果相一致。对反应轨线的研究表明,该反应为一直接反应,而且反应碰撞在低及高的碰撞参数下的机理不一样,在低碰撞参数下反应碰撞是直接完成的,产物HCl以向后散射为主,转动基本上是冷的,但比高碰撞参数下的热。在高的碰撞参数下则生成短寿命的碰撞复合物,产物 相似文献
13.
在140℃下,以3-溴-4-甲基苯甲酸和咪唑为配体,通过水热法在甲醇/水混合溶剂中反应24 h合成了锌(Ⅱ)配合物Zn(C3H4N2)2(C8H6O2Br)2。通过元素分析、红外光谱、热重分析和X射线粉末衍射对配合物进行了结构表征,同时用X射线单晶衍射分析确定了其晶体结构。结果表明,其晶体属单斜晶系,空间群为C2/c,晶胞参数:a=13.257(3),b=9.765(2),c=20.494(4),β=107.79(3)°,V=2526.3(9)3,Dc=1.655g·cm-3,μ=4.170mm-1,F(000)=1248,Z=4,最终残差因子R1=0.0552,wR2=0.1378。配合物为单核结构,中心锌(Ⅱ)离子与来自2个3-溴-4-甲基苯甲酸根的2个O原子及2个咪唑分子的2个N原子配位,形成了畸变的四方锥几何体。晶体内,分子间则通过N—H…O氢键作用在ab面形成了层状结构。研究了配合物的发光性质。 相似文献
14.
Isochoric PVTx measurements have been performed for the binary system of nitrous oxide + CH 3F (R41), +CH 2F 2 (R32), and +CHF 3 (R23) using a new experimental set-up. The experiments covered both the two-phase region and the superheated vapor region and were performed within the temperature range 214–358 K and within a pressure range from 270 to 5600 kPa. Data have been collected for not less than four compositions for each system. The vapor–liquid equilibrium data were derived correlating the experimental data by means of the Carnahan–Starling–De Santis equation of state. The studied systems show a positive deviation from the Raoult's law. The results obtained were compared with the Burnett PVTx data. The two methods showed a mutual consistency within an acceptable margin of error. No other experimental PVTx data were found in the literature for these binary systems. 相似文献
15.
The preparation and properties of complexes of the general formulae [Rh(TFB)(diolefin)]ClO 4, [Rh(TFB)(arene)]ClO 4 and [Rh(TFB)L 2]ClO 4, (TFB = tetrafluorobenzobarrelene, L = dimethylsulfoxide and tetrahydrothiophen) are described. The crystal structures of the arene complexes (arene = C 6Me 6, C 6H 3Me 3 and C 6H 4Me 2) have been solved by X-ray methods. The three compounds crystallize in quite similar lattices: R3 c, a = b = 27.122, 26.233, 25.731 and c = 17.079, 16.388, 16.256 Å, respectively. δ R-plots for about 2000 reflections show the agreement in the refinements carried out up to R-values of 5%, 5% and 4% respectively. The Rh atom is coordinated to the double bonds of the TFB and to the arene ring in all three compounds, but the deviation from planarity of the arene and its relative position with respect to the TFB moiety varies. 相似文献
16.
The adsorption of C 2H 4 on W(100) has been studied by ultraviolet photoelectron spectroscopy with hν = 21.22 eV. The spectrum measured after in initial saturation exposure at 80 K exhibits structure which correlates well with energy levels recently calculated by Demuth and Eastman (DE) for sp 3 rehybridized C 2H 4. Dehydrogenation of the adsorbate, either by subsequent heating to 295 K or direct adsorption at 295 K, yields a spectrum which correlates with DE's calculation for sp 2 rehybridized C 2H 2. These results suggest that C 2H 4 and C 2H 2 may be distorted from their planar and linear structures respectively and that the CC bonds on these molecules are stretched by adsorption on W(100). Qualitative arguments suggest that the bonding site for both melecules is directly over a W atom and that the Dewar—Chatt model for πd bonding in organometallic compounds is applicable. 相似文献
17.
Rate constants for the reaction of O( 3P) atoms with C 3H 4, C 3H 6 and NO(M = N 2O) have been measured over the temperature range 300–392°K using a modulation-phase shift technique. The Arrhenius expressions obtained are:C 2H 4, k2 = 3.37 × 10 9 exp[?(1270 ± 200)/ RT]liter mole ?1 sec ?1,C 3H 6, k2 = 2.08 × 10 9 exp[?(0 ± 300)/ RT]liter mole ?1 sec ?1,NO(M = N 2O), k1 = 9.6 × 10 9 exp[(900 ± 200/ RT]liter 2 mole ?2 sec ?1.These temperature dependencies of k2 are in good agreement with recent flash photolysis-resonance flourescence measurements, although lower than previous literature values. 相似文献
18.
We report the surface-enhanced Raman spectra of ethylene and acetylene adsorbed on colloidal silver particles formed by gas aggregation and isolated at low temperatures in solid adsorbate/argon matrices. The spectra of both molecules exhibit modes which are normally Raman-forbidden. Excitation with several visible laser frequencies indicated that the degree of enhancement increased towards the blue. 相似文献
19.
A new vanadium(III) phosphite, (C 4H 8N 2H 4) 0.5(C 4H 8N 2H 3)[V 4(HPO 3) 7(H 2O) 3]1.5H 2O, has been synthesized hydrothermally by using V 2O 5, H 3PO 3 as reactants, piperazine as the structure-directing agent. The as-synthesized product was characterized by powder X-ray diffraction, IR spectroscopy, inductively coupled plasma analysis, thermogravimetric analysis, and SQUID magnetometer. Single-crystal X-ray diffraction analysis shows that the title compound crystallized in the trigonal space group (No. 165) with the parameters: , , and Z=4. Its structure is built up by alternation of octahedral VO 6 or VO 5(H 2O) and pseudo-pyramidal HPO 3 units to form infinite 2D layers, and these layers are interconnected by sharing vertex-oxygen with octahedral VO 6 units to generate a 3D open-framework structure with 12-membered ring channels in a and b directions, respectively, where there exist entrapped diprotonated and mono-protonated piperazine cations, and water molecules. Magnetic measurement indicates that paramagnetic behavior is observed down to 4 K. 相似文献
20.
Three tin (Ⅳ) complexes with N,N-dialkyl dithiocarbamates Ph 3SnS 2CN(CH 3)C 6H 5 ( 1),Ph 3SnS 2CN(C 4H 8NH) ( 2) and Sn(Cl) 2(S 2CNEt 2) 2 ( 3) have been synthesized. The crystal structures have been determined by X-ray sin- gle crystal diffraction. A crystal of the complex 1 is triclinic with space group P1, a=0.9485(3)nm, b=1.0491(3)nm, c=1.3631(4)nm, α=70.996(4)°, β=72.294(4)°, γ=79.609(4)°, Z=2, V=1.2168(6)nm 3, Dc=1.453g·cm -3, μ=1.234mm -1, R=0.0442, wR=0.0858. A crystal of the complex 2 is monoclinic with space group P2(1)/ c, a=1.2214(2)nm, b=1.1651(2)nm, c=1.5769(3)nm,β=99.039(2)°, Z=2, V=2.2162(7)nm 3, Dc=1.532g·cm -3, μ=1.352mm -1, R=0.0267, wR=0.0591. A crystal of the complex 3 is triclinic with space group P1, a=0.7179(2)nm, b=0.9256(3)nm, c=1.5327(5)nm,α=93.857(4)°,β=98.992(4)°, γ=109.481(4)°, Z=2, V=0.9405(5)nm 3, Dc=1.717g·cm -3, μ=2.076mm -1, R=0.0263, wR=0.0662. In the complexes 1 and 2 the tin atoms rendered five-coordination in a distorted tigonal bipyramidal structure and in the complex 3 the tin atom rendered six-coordination in a distorted octahedron structure. CCDC: 1, 179918; 2, 180024; 3, 180004. 相似文献
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