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1.
Mechanism and Kinetics of Thermal Dissociation of Inclusion Complex of β-Cyclodextrin and 1-Methylcyclopropene 总被引:1,自引:0,他引:1
Yi He Ting Sun 《化学物理学报》2006,19(1):89-92
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B3LYP level density functional theory (DFT) and multiconfiguration self-consistent-field (MCSCF) level ab initio method calculations have been performed on the basis of relativistic effective core potentials to investigate the nature of EuC and EuC2 molecules. The computed results indicate that the ground states of EuC and EuC2 are ^12∑^+ and SA2, respectively. Dissociation potential energy curves of the low-lying electronic states of EuC have been calculated using the MCSCF method, and the same level calculation on EuC2 indicates that the dissociation energy of EuC2 of ground state compares well with the available experimental data. The bond characteristic is also discussed using Mulliken populations. 相似文献
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We have calculated vibronic spectra of the first electronic nπ* transitions of pyridine and pyrimidine in the isolated state using the DFT method in the Franck-Condon approximation. Vibrational spectra for the ground and excited states have been calculated in the anharmonic approximation, which allowed us to refine the assignment of normal vibrations of pyridine and pyrimidine. We have done a complete interpretation of the vibrational structure of the absorption and fluorescence spectra of pyridine and pyrimidine. It has been shown that Fermi resonances between fundamental and combination vibrations and overtones 12 and 16b + 4, 6a and 2 × 16b affect the formation of the vibrational structure of electronic spectra of pyrimidine. Good agreement between calculated and experimental spectra confirms the correctness of the models of the two molecules in their ground and excited states, which makes it possible to use the models in further investigations of various properties of these molecules in electronically excited states, e.g., tautomerism of pyrimidine bases of nucleic acids. 相似文献
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John E BarnesPaul B Hays 《Journal of Molecular Spectroscopy》2002,216(1):98-104
Measurements of pressure shift and pressure broadening in molecular oxygen have been made for rotational transitions in the B (1←0) and γ (2←0) vibrational bands of the b1Σ+g←X3Σ−g visible electronic transition. The absorption features were measured simultaneously in two cells by photoacoustic spectroscopy using a scanning dye laser. The measurements were made with background gases of both pure oxygen and air at room temperature. The pressure shifts were all negative. The measurements show the magnitude of the pressure shift increasing with vibrational quantum number when compared with existing data for the A (0←0) band. The shifts also increase with rotational number within each vibrational band. The shifts in air are larger than in oxygen although the difference gets smaller with vibrational number. The average shifts in air for the A, B, and γ bands were 36, 11, and 0.2% higher, respectively, than in pure oxygen. The pressure broadening of the rotational lines does not change significantly with vibrational number and in general decreases with rotational number within a band. The pressure shift measurements were used by the high-resolution Doppler imager (on the Upper Atmospheric Research Satellite) to correct the Doppler wind measurements. 相似文献
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V. Barger W. Y. Keung R. J. N. Phillips 《Zeitschrift fur Physik C Particles and Fields》1980,6(2):169-174
We show that inclusive ψ hadroproduction cross sections andx F -distributions are quantitatively consistent with calculations based on the lowest order \(q\bar q \to c\bar c\) andgg→ \(c\bar c\) QCD subprocesses using a duality ansatz. Data in the πN, KN, NN and \(\bar NN\) channels are considered. They provide determinations of the gluon distributions within the nucleon, the pion, and the kaon at the ψ mass scale. AvailableNN→ΥX data aty=0 are consistent with the same model, using gluon distributions appropriate to the Υ mass: predictions ofx F -distributions are made. 相似文献
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The Mn Lα and Lβ spectra of Mn, MnO, Mn3O4, Mn2O3, and MnO2 have been measured. Each Mn La spectrum has been deconvoluted into two bands, LαA and LαB, and the integrated LαA/LαB intensity ratio was found to be inversely proportional to the Mn-0 inter-atomic distance, but proportional to the oxidation number. This finding tends to indicate the likelihood of crossover transition from oxygen to manganese. The intensity ratio Lβ/LαB of the pure metal was found to coincide closely with the statistically predicted value of 0.5. Furthermore, for Mn-metal, as well as for the oxides, the shift of the LαA band from the LαB band was found to agree with the change in the Lβ/Lα peak intensity ratio as a function of oxidation number. 相似文献
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CHENJian-Gang GUOChang-Xin ZHANGLin-Li HUJun-Tao 《中国物理快报》2004,21(7):1366-1369
Hexagonal ZnO microrods and sub-microrods have been prepared through thermal decomposition of an equimolar (0.1 M) aqueous solution of Zn(NO3)2.4H20 and (CH2)6N4 a~t 90~C for different times (10-46h). The microrods were transformed into hollow hexagonal ZnO microtubes when the growth time reached 46 h. The Raman spectra and the photoluminescent (PL) spectra were measured. The PL spectra of microrods consist of two strong narrow near-UV bands at 380 nm and 400 nm assigned to free exciton emission and exciton-exciton collision, respectively.The PL spectrum of ZnO microtubes show only one peak in the near-UV region with peak located at 380nm with FWHM of about 20nm assigned to free exciton emission. When the growth time increased, the peak intensity of near-UV band decreased. 相似文献
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DENG Baiquan HUANG Jinhua FENG Kaiming CHEN Zhi 《核工业西南物理研究院年报(英文版)》2005,(1):108-110
The ftrst numerical simulation code package WITRIM has been developed to calculate the tritium inventory distribution and time-evolution in all sub-systems of FEB fusion reactor. The applications during recent six years indicate that it is reasonable and fully admitted by colleagues abroad. Some creative papers with new concept are published. For instance, we first time pointed out a new phenomenon of "tritium well depth and tritium well time" during the fusion reactor start-up phase. This is somewhat similar to, but quite different from the "iodine well depth and iodine well time" poisoning problem during restart-up process of a fission reactor. The authors not only proposed but also numerically solved this new phenomenon. The combination of the SWITRIM code package, user's guide, and application example are briefly introduced in this article. 相似文献
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In this paper various structural possibilities for AlnO neutral and cationic isomers were investigated by using the B3LYP/6-311G(3df) method. Calculations of this paper predicted the existence of a number of previously unknown isomers. The stabilities of the AlnO (n = 2 - 7) clusters with even n are greater than those with odd n, however the stabilities Of cationic ions have the opposite odd-even alternation. The mass spectra observations of Al17O^+ and Al19O^+ ions support our theoretical predictions on their stabilities. 相似文献
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Ya.I. Azimov 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):209-219
Isospin-violating mixing of ρ- and ω-mesons is reconsidered in terms of propagators. Its influence on various pairs of (ρ,ω)-decays
to the same final states is demonstrated. Some of them, (ρ,ω)↦π+π- and (ρ,ω)↦πγ, have been earlier discussed in the literature, others (e.g., (ρ,ω)↦ηγ and (ρ,ω)↦e
+
e
-) are new in this context. Changes in partial widths for all the decay pairs are shown to be correlated. The set of present
experimental data, though yet inconclusive, provides some limits for the direct (ρω)-coupling and indirectly supports enhancement
of ρ↦πγ in comparison with ρ±↦π±γ, though not so large as in some previous estimates.
Received: 16 September 2002 / Accepted: 23 September 2002 / Published online: 4 February 2003
RID="a"
ID="a"e-mail: azimov@pa1400.spb.edu
Communicated by V.V. Anisovich 相似文献
14.
Yuan‐zhi Song 《光谱学快报》2013,46(6):811-833
The geometric parameters, vibrational frequencies, and the thermochemical values of o‐benzoquinone (o‐BQ), p‐benzoquinone (p‐BQ), pyrocatechol (PC), and p‐hydroquinone (p‐HQ) were computed using ab initio calculation (HF) and density functional theory (DFT) with the 6‐31G (d) and 6‐31G (d, p) basis sets, respectively. Cyclic voltammetry with a gold electrode of PC solutions in phosphate buffers at pH 7.30 showed that the standard electrode potential of half reaction for o‐BQ and PC is 0.813 V. The standard electrode potential of half reaction for o‐BQ and PC with a p‐BQ, H+/p‐hydroquinone (p‐HQ) reference electrode, using the solvation energies and the sum of electronic and thermal free energies of o‐BQ and PC, is consistent with the experimental one. 相似文献
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A model of the grain-boundary self-diffusion process in metals undergoing phase transitions in the solid state is proposed. The model is based on the ideas and approaches of the theory of nonequilibrium grain boundaries. It is shown that the range of application of basic relations of this theory can be extended, and they can be used to calculate the parameters of grain-boundary self-diffusion in high-temperature and low-temperature phases of metals with phase transition. Based on the constructed model, activation energies of grainboundary self-diffusion in titanium and zirconium are calculated, and their anomalously low values in the low-temperature phase are explained. The calculated activation energies of grain-boundary self-diffusion are in good agreement with experimental data. 相似文献
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《声学学报:英文版》1997,(2)
I.IntroductionStabilityofatransducerisveryimportantinultrasonicinspecting.Resultsdetectedwithatransducerwillbeunreliableifitscharacteristicvarieswithtemperatureandpressure.Ininspectingoil-wellcementingqualitybyultrasonicechoes,forexample,thebondingqualitiesareevaluatedaccordingtoaspecificstandard.Temperatureandpressureinwellsvarywithdepth.Ifatransducercharacteristicvariesobviouslywithtemperatureandpressure,eva.luatingresultswillbeaffected.Asweknow,itisverydifficulttokeepatransducercharacteri… 相似文献
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Artur M. S. Silva Hilário R. Tavares Ana I. N. R. A. Barros José A. S. Cavaleiro 《光谱学快报》2013,46(8):1655-1667
New 2′-hydroxychalcone and flavone derivatives have been synthesised. Their [1H] and [13C] NMR spectra were assigned by the application of COSY and HETCOR experiments and allowed the discussion of some structural aspects. It was shown on the basis of NOE experiments some configurational and conformational features of both type of compounds. 相似文献
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Oleinikov A. D. Mebel A. M. Azyazov V. N. 《Bulletin of the Lebedev Physics Institute》2020,47(3):97-100
Bulletin of the Lebedev Physics Institute - Abstract—Quantum-mechanical ab initio calculations are applied to study the growth mechanism of polycyclic aromatic hydrocarbons via reactions of... 相似文献
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S.CHAKRABARTY 《声学学报:英文版》1992,(2)
The non-linear theory of vibration has recently been applied toa number of problems in physics and was found to give many interestingresults which were absent in the case of linear vibration.It is natural tothink of the outcome of application of non-linear theory to raga music,atopic which has hitherto been unexplored.It has been found that a newrealm of musical idea is obtained if one considers the effects ofnon-linearity in physics on the understanding of the aesthetics and beautyin raga music when two notes are sounded simultaneously. 相似文献