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151.
A 285-pomt multi-reference configuration-interaction involving single and double excitations ( MRS DCI) potential energy surface for the electronic ground state of L12H is determined by using 6-311G (2df,2pd)basis set.A Simons-Parr-Finlan polynomial expansion is used to fit the discrete surface with a x2 of 4.64×106 The equn librium geometry occurs at Rc=0.172 nm and,LiHL1=94.10°.The dissociation energy for reaction I2H(2A)→L12(1∑g)+H(2S) is 243.910 kJ/mol,and that for reaction L12H(2A')→HL1(1∑) + L1(2S) is 106.445 kl/mol The inversion barrier height is 50.388 kj/mol.The vibrational energy levels are calculated using the discrete variable representation (DVR) method. 相似文献
152.
Jiang Hu Wei‐Dong Zhang Yun‐Heng Shen Chuan Zhang Run‐Hui Liu Xi‐Ke Xu Bin Wang 《Helvetica chimica acta》2007,90(4):720-722
Two novel alkaloids, 4,5‐dihydroxy‐1‐methyl‐3‐oxo‐2‐(trichloromethyl)‐3H‐indolium chloride ( 1 ) and 4‐(2‐methoxyethyl)‐N,N‐dimethylbenzenamine ( 2 ), were isolated from the EtOH extract of the roots of Zanthoxylum nitidum. Their structures were identified on the basis of spectroscopic and mass‐spectrometric analyses. 相似文献
153.
以2-氨基-5-氟苯甲酸为起始原料,与醋酐酰化关环制得6-氟-2-甲基噁嗪-4-酮(1); 1在80%水合肼中回流反应制得6-氟-2-甲基-3-氨基-4(3H)-喹唑啉酮(2); 2分别与羟基芳醛和杂环芳醛反应合成了6个6-氟-4(3H)-喹唑啉酮类Schiff碱(3a~3f),其中3b~3f为新化合物,其结构经1H NMR, 13C NMR, IR和元素分析表征。采用琼脂扩散法研究了3a~3f对大肠杆菌、金黄色葡萄球菌和枯草杆菌的抑制活性。结果表明:用药浓度为400 μg·mL-1时,3a~3f对受试菌种均有一定的抑制活性,其中6-氟-2-甲基-3-(4-吡咯苯亚甲氨基)-4(3H)-喹唑啉酮(3c)抑菌活性最强,对大肠杆菌和枯草杆菌的抑菌圈直径分别为9.38 mm和9.00 mm。 相似文献
154.
聚氯乙烯(PVC)材料广泛应用于建筑、电讯、交通、电子、化工、包装等行业。然而,PVC加工时存在着一个致命的弱点,就是其流动温度为136℃,分解温度为140℃,两者相差仅4℃,给加工带来很大难度,为了能顺利加工就必须加入热稳定剂,热稳定剂是PVC加工不可缺少的主要助剂之一。热稳定剂种类繁多,我国目前大量使用的稳定剂为铅盐及金属皂等稳定剂,产量高达4.5万吨。由于铅、镉、钡等金属元素具有一定的毒性,使用中易造成环境污染,有害于人体健康,因此必须严格加以控制。 相似文献
155.
Hui Li 《Tetrahedron letters》2006,47(20):3485-3488
A general entry to C(1) aryl-substituted glycals from the corresponding sugar lactones is described. This approach features one-pot access to aryl glycals. A variety of aryllithium reagents can be used and the method is compatible with various 2-deoxysugar lactones. 相似文献
156.
0IntroductionThe solid-state chemistry of manganese!car-boxylate coordination polymers has received growingattention over the past few years,owing to their fasci-nating network topologies and potential application inthe field of molecular magnetism and bi… 相似文献
157.
0IntroductionRareearthsarenowappliedwidelyinChina,whichcanimprovecropsyieldsandthetheirqualit-ies犤1犦.Thebeneficialeffectsmaybeduetothestimu-latoryeffectsoftheseelementsonthenutrientuptakebyplantsorontheincreasingofchlorophyllsynthesisintheplants犤2犦.Whilealotofresearcheshavebeendoneontheimprovednutritionofcropsafterapplica-tionofrareearths,muchlessattentionhasbeenpaidtothedeteriorationofsoilqualityduetotheapplicationofrareearthsforyears犤3犦.Scientistshavediscoveredthataccumula… 相似文献
158.
A procedure for the Raman spectra calculation of vitreous and molten silicates was presented in this paper. It includes molecular dynamics MD simulation for the generation of equilibrium configurations, Wilson's GF matrix method for the calculations of eigenfrequencies and corresponding vectors, electro-optical parameters method (EOPM) for the Raman intensity calculations, and the bond polarizability model (BPM) for the determination of polarizability and polarizability derivative. One of the most important characteristics of this procedure is the achievement of the partial Raman spectra of five tetrahedral units, as well as the total spectral envelope. In this paper, the calculation was carried out for the vitreous and molten calcium silicates with different compositions and at various temperatures. It is worthwhile to note that the calculation is based on statistical configurations distribution in the space and so it is not needed to artificially adjust the full width at half maximum (FWHM) of spectra. It was also tested through the good agreement of the calculated spectra with the experimental, including some regularity of spectral properties. According to the calculation, the symmetrical stretching of whole tetrahedral units, to which the stretching of Si-O(nb) bond gives the main contribution to intensity, is proven to be the dominance in the high-frequency range (800-1200 cm(-1)) and the symmetrical bending of Si-O(b)-Si, to which the stretching of Si-O(b) bond exhibits the main contribution, is the dominance in the medium-frequency range (400-700 cm(-1)). As the first theoretical results, the Raman scattering coefficient of each Q(i) was found little change along with the variation of composition and temperature. 相似文献
159.
Electrostatic fields produced by flat electrodes are often used to manipulate particles in solution. To study the field produced by such an electrode, we consider the problem of an infinite strip of width 2a with imposed constant potential immersed in an electrolyte solution. Sufficiently close to the edge of the strip, the solution is determined by classical electrostatics and results in a field singularity. We examine two limiting cases, (a) when strip width a<1k, the Debye screening length, and (b) when strip width is much greater than the Debye screening length, a>1k. We present exact results for the two cases in the limit of small potentials where the Poisson-Boltzmann equation can be linearized. By drawing on an analogy with antiplane shear deformations of solids, and by employing the path-independent J integral of solid mechanics, we present a new method for determining the strength of the edge singularity. The strength of the singularity defines an exact near-field solution. In the far field the solution goes to that of a line of charge. The accuracy of the solution is demonstrated by comparison with the numerical solutions of the Poisson-Boltzmann equation using the finite element method. 相似文献
160.