共查询到20条相似文献,搜索用时 15 毫秒
1.
M. V. Zagidullin R. I. Kaiser M. Ahmed D. P. Porfiriev I. A. Medvedkov A. M. Mebel V. N. Azyazov 《Bulletin of the Lebedev Physics Institute》2018,45(10):314-317
The temperature and pressure-dependent rate constants for the process C10H7Br ? C10H7+Br were evaluated using the variable reaction coordinate transition state theory VRC-TST. The calculated rate constants and computational fluid dynamics (CFD) calculations were employed to estimate the pyrolysis efficiency of 2-bromonaphthalene in the resistively-heated SiC high-temperature “chemical reactor” at the temperature of about 1500 K. The observed 40% pyrolysis efficiency is reproduced by CFD calculations if the value of the calculated rate constant for the C10H7Br pyrolysis is increased by a factor of 2. 相似文献
2.
Molecular structure of tris(acetylacetonato)scandium, Sc(C5H7O2)3, is investigated by gas-phase electron diffractometry. The main structural parameters of the molecule are evaluated. The
average intemuclear distances and angles correspond to C3 symmetry. The chief structural motif is trigonal antiprisms of six oxygen, carbon, and hydrogen atoms with a scandium atom
at the center. It is found that rg[Sc-O) = 204.1(8) pm and rg(C−O) = 124.7(4) pm
Translated fromZhurnal Struktumoi Khimii, Vol. 39, No. 4, pp. 633–639, July–August, 1998. 相似文献
3.
Potential Energy Surface for Oxidation of Indenyl C<Subscript>9</Subscript>H<Subscript>7</Subscript>
A. R. Ghildina A. M. Mebel V. N. Azyazov 《Bulletin of the Lebedev Physics Institute》2018,45(10):291-294
Ab initio calculations were performed to obtain local energy extrema, including an effect of reagents, intermediates, and reaction products on the potential energy surface for the C9H7+O2 reaction, playing a significant role in oxidation of polycyclic aromatic hydrocarbons at combustion conditions. The final products, determined as a result of the calculations are styrenyl radical C8H7+CO2, ortho-vinyl phenyl radical C8H7+CO2 and 1-H-inden-1-one C9H6O+OH, which is predicted to be the prevailing reaction product. 相似文献
4.
N. A. Ivanova A. A. Onischuk S. V. Vosel P. A. Purtov L. V. Kulik L. L. Rapatskiy N. T. Vasenin V. F. Anufrienko 《Applied magnetic resonance》2009,35(4):625-637
The paper is devoted to electron paramagnetic resonance investigation of nanoparticles and aggregates of nanoparticles formed
by pyrolysis of propane as well as a mixture of propane and iron pentacarbonyl. The measurement showed that the pyrolysis
of the C3H8 plus Ar mixture results in the formation of a carbonaceous phase (phase I), which is quite different from that formed by
the C3H8 plus Fe(CO)5 plus Ar mixture (phase II). In phase I there is a strong oxygen effect for as-prepared samples; 75% of spins are accessible
to the environmental gas via the interconnected system of microvoids and microchannels. In phase II there was a weak oxygen
effect for the as-prepared samples. However, after exposition of phase II to air for 160 h, the properties of phase II have
become about the same as that of phase I. A strong oxygen effect was observed for the air-exposed phase II. The line width
for phase II increases monotonically with the iron content in the sample. This increase is probably related to the dipole-dipole
interactions between the radical centers and the iron atoms distributed throughout the carbon matrix. 相似文献
5.
We have carried out experimental and theoretical
studies on electron scattering from the C3H6 isomers and
C3F6 molecules and we report on total, differential as well
as theoretical integral elastic cross-sections for these
molecules. Vibrational excitation functions are also presented for
the typical vibrational peaks in C3H6 and cyclo-C3H6
for the angle of 90○, impact energy range of 1–16 eV
and loss energies of 0.12 eV and 0.13 eV, respectively. In the
cross-sections, clear differences in peak positions and magnitudes
between the C3H6 isomers can be viewed as the isomer effect.
The same is observed between C3H6 and C3F6 in a clear
manifestation of the fluorination effect. The resemblance of the
π* shape resonance in the cross-sections, observed at about
2.2 eV for C3H6 and 3.5 eV for C3F6, to those in
C2H4 and C2F4 clearly points to the effect of the
double bond in the molecular structures for these molecules.
Theoretical analysis is performed to provide rationales for the
scattering dynamics. 相似文献
6.
V. Ya. Basevich A. A. Belyaev S. M. Frolov 《Russian Journal of Physical Chemistry B, Focus on Physics》2010,4(4):634-640
A previously proposed algorithm of constructing optimal mechanisms of the low- and high-temperature oxidation and combustion
of normal alkanes was applied to n-hexane. The proposed mechanism can be considered a nonempirical detailed mechanism, since all the constituent reactions have
a solid kinetic substantiation. The mechanism features two main peculiarities: it contains no reactions of double oxygen addition
(first to the peroxide radical and then to its isomerized form) and (2) involves no isomeric compounds and derivatives thereof.
Application of the algorithm to n-hexane made it possible to create a new compact kinetic mechanism. The mechanism was demonstrated to correctly describe the
multistage character of low-temperature self-ignition: the appearance of a cool and then a blue flame. 相似文献
7.
R. B. Lyubovskii S. I. Pesotskii G. V. Shilov E. I. Zhilyaeva A. M. Flakina R. N. Lyubovskaya 《Journal of Experimental and Theoretical Physics》2016,122(2):318-327
We study the effect of interionic anisotropy on the phase states of a non-Heisenberg ferromagnet with magnetic ion spin S = 1. It is shown that depending on the relation between the interionic anisotropy constants, uniaxial and angular ferromagnetic and nonmagnetic phases exist in the system. We analyze the dynamic properties of the system in the vicinity of orientational phase transitions, as well as a phase transition in the magnetic moment magnitude. It is shown that orientational phase transitions in ferromagnetic and nematic phases can be first- as well as second-order. 相似文献
8.
S. O. Adamson 《Russian Journal of Physical Chemistry B, Focus on Physics》2016,10(1):143-152
The stationary points of the potential energy surfaces for the reactions C2H2 + OH and C2 + H2O are calculated using density functional theory and the coupled cluster method. The relative energies and geometric parameters of the stable intermediates and transition states are in good agreement with the results of independent studies. In most cases, the relative energies differ from the earlier published values by no more than 3 kcal/mol, whereas the rotational constants, by 1–2%. The mechanism of the reaction CCOH2 → C2 + H2O is studied in detail. The possible sources of errors in the calculation methods are examined. 相似文献
9.
10.
11.
The Sm3+ ion in the Cs2NaYF6 single crystal was studied by optically detected electron paramagnetic resonance spectroscopy. Magnetic resonance signals
were recorded by Faraday rotation at the frequency of 0.6–0.85 GHz and magnetic fields of about 0.14 T. The hyperfine parameters
of 147Sm3+ and 149Sm3+ isotopes were determined. 相似文献
12.
R. B. Lyubovskii S. I. Pesotskii V. I. Nizhankovskii W. Biberacher R. N. Lyubovskaya 《Journal of Experimental and Theoretical Physics》2004,98(5):1037-1039
The behavior of de Haas-van Alphen oscillations in the quasi-2D organic metal (ET)8[Hg4Cl12(C6H5Cl)2] was studied in detail. The section of the Fermi surface of this metal is a two-dimensional network of magnetic breakdown orbits. Only two frequencies, which corresponded to allowed closed orbits, FA and FMB, were detected. This is in agreement with the earlier studies of Shubnikov-de Haas oscillations in this metal. The reason for the absence of other allowed frequencies remains unclear. The angular dependences of the amplitudes of FA and FMB oscillations contain a series of “spin zeros.” An analysis of their positions led us to suggest that many-particle interactions were weakened in (ET)8[Hg4Cl12(C6H5Cl)2]. 相似文献
13.
A Cu2+-doped single crystal of catena-trans-bis(N-(2-hydroxyethyl)-ethylenediamine) zinc(II)-tetra-m-cyanopaladate(II) [ZnPd(CN)4(C4H12N2O2)] complex has been investigated by electron paramagnetic resonance (EPR) technique at room temperature. EPR spectra indicate
that Cu2+ ions substitute for magnetically equivalent Zn2+ ions and form octahedral complexes in [ZnPd(CN)4(C4H12N2O2)] hosts. The crystal field affecting the Cu2+ ion is nearly axial. The optical absorption studies show two bands at 322 nm (30864 cm−1) and 634 nm (15337 cm−1) which confirm the axial symmetry. The spin Hamiltonian parameters and the relevant wave function are determined. 相似文献
14.
15.
The Ac electrical conductivity and the dielectric relaxation properties of the [(C3H7)4N]2Cd2Cl6 polycrystalline sample have been investigated by means of impedance spectroscopy measurements over a wide range of frequencies
and temperatures, 209 Hz–5 MHz and 361–418 K, respectively. The purpose is to make a difference between the electrical and
dielectric properties of the polycrystalline sample and single crystal. Besides, a detailed analysis of the impedance spectrum
suggests that the electrical properties of the material are strongly temperature-dependent. Plots of (Z" versus Z') are well
fitted to an equivalent circuit model consisting of a series combination of grains and grains boundary elements. Moreover,
the temperature dependence of the electrical conductivity in the different phases follows the Arrhenius law and the frequency
dependence of σ (ω) follows the Jonscher’s universal dynamic law. Furthermore, the modulus plots can be characterized by full
width at half height or in terms of a nonexperiential decay function φ(t) = exp(t/t)β. Finally, the imaginary part of the permittivity constant is analyzed with the Cole–Cole formalism. 相似文献
16.
Josep Batle Ahmed Farouk Majid Alkhambashi Soliman Abdalla 《The European Physical Journal B - Condensed Matter and Complex Systems》2017,90(3):49
Quantum correlations are generally impossible to address directly in bulk systems. Quantum measures extended only to a few number of parties can be discussed in practice. In the present work we study a cluster of spins belonging to a compound whose structure is that of a quantum magnet. We reproduce at a much smaller scale the experimental outcomes and then we study the role of quantum correlations there. A macroscopic entanglement witness has been introduced in order to reveal quantum correlations at nonzero temperatures. The critical point beyond which entanglement is zero is found at T c = 15 K. 相似文献
17.
Samira Moniri Mohammad Reza Hantehzadeh Mahmood Ghoranneviss Mohsen Asadi Asadabad 《Optical and Quantum Electronics》2017,49(4):174
Platinum nano sized particles (Pt NPs) are superior catalysts for many intentions, such as glucose sensors, cancer therapy, gas sensors, etc. Here, Pt NPs were produced by pulsed laser ablation in C2H6O2 solution using Q-switched Nd:YAG laser, for the first time. Then, the influence of the laser fluence during synthesis of them was investigated; and they were characterized by UV–vis spectroscopy, TEM, FE-SEM, XRD, FT-IR, and Raman spectroscopy. The results showed that with increasing laser fluence, the mean particle size of the spherical NPs enhanced. Meanwhile, they had a polycrystalline cubic structure. Correspondingly, the plasmon peak position of generated NPs in the absorption spectra shifted from 257 to 266 nm, with a rise of laser fluence. The IR and Raman spectroscopy was used to achieve the information about the surface state of Pt NPs. We propose that the optimum adjusted laser fluence is an important factor to increase the ablation efficiency. 相似文献
18.
Q. Ren X. Q. Wang H. L. Yang G. H. Zhang X. B. Sun W. F. Guo F. J. Zhang X. Zhang Y. T. Chow D. Xu 《Laser Physics》2007,17(8):1058-1061
A novel dmit organometallic complex—[(C4H9)4N][Co(dmit)2] (dmit2? = 4,5-dithiolate-1,3-dithiole-2-thione), abbreviated as BuCo, is synthesized and its third-order optical nonlinearity of the acetone solution is characterized using the Z-scan technique with a 40-ps pulse width at 1064 nm. Z-scan curves show that BuCo sample solution possesses the negative nonlinear refraction, exhibiting a self-defocusing effect. In addition, the two-photon absorption has been observed in BuCo. The effective molecular second-order hyperpolarizability γeff of the BuCo molecule was estimated to be as large as 5.60 × 10?31 esu, suggesting BuCo is a potential material for optical device applications. 相似文献
19.
The [N(CH3)4][N(C2H5)4]ZnCl4 compound has been synthesized by a solution-based chemical method. The X-ray diffraction study at room temperature revealed
an orthorhombic system with P21212 space group. The complex impedance has been investigated in the temperature and frequency ranges 420–520 K and 200 Hz–5 MHz,
respectively. The grain interior and grain boundary contribution to the electrical response in the material have been identified.
Dielectric data were analyzed using the complex electrical modulus M
* for the sample at various temperature. The modulus plots can be characterized by full width at half height or in terms of
a non-exponential decay function ϕ(t) = exp[(−t/τ)
β
]. The detailed conductivity study indicated that the electrical conduction in the material is a thermally activated process.
The variation of the AC conductivity with frequency at different temperatures obeys the Almond and West universal law. 相似文献
20.
Results are presented from studies of the electric and emission parameters of transverse volume discharges in neon-sulfur-hexafluoride-propane mixtures at a total pressure of 3–12 kPa. The spatial characteristics of a transverse volume discharge, the plasma radiation spectra in the 130- to 550-nm wavelength range, the waveforms of the discharge voltage and current, and the yield of carbonic products of propane decomposition are investigated at different pressures and different composition of the Ne-SF6-C6H14 mixture. 相似文献