The detailed rotational spectrum of the linear molecule cyanobutadiyne, H(CC)2CN, has been observed in the range 26.5 to 40.0 GHz. In particular, a study has been made of transitions belonging to the vibrationally excited states (including combination states) of the degenerate vibrations ν10 and ν11. Particular attention has been focused upon two series of satellites: one in which v11 = 1–8 and a second in which v10 = 1 while v11 varies from 1–7 for a given J transition. The analysis was performed using a least-squares criterion to fit all the transitions simultaneously. In addition to providing confirmation of the forms of the vibrational and rotational l-resonance matrix elements, the analysis has demonstrated that the widely spaced l quartets observed in combination states with odd Σivi can be attributed to a strong mixing of the four l = 1 states by vibrational l resonance. It has also been found that it is only possible to determine the sign of the product of the offdiagonal parameters and not the sign of any one parameter. Therefore the reported assignment is not unique. As confirmation of the validity of the analysis, the computer simulation of the spectrum is compared with that observed. 相似文献
We describe the generation of aligned carbon nanotube bundles and films by pyrolysis of solid organic precursors (for example 2-amino-4,6-dichloro-s-triazine, s-triaminotriazine) at 950-1050 °C over laser-patterned thin metal (Fe, Co, Ni) films, deposited on silica substrates. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies reveal that surface roughness of the laser-etched catalytic substrates plays a key role in achieving control of nanotube growth. We believe that, during the etching process, the energised (ablated) metal clusters condense and recrystallise evenly, possibly as the metal oxide, within the edges or surface of the eroded regions. During pyrolysis these catalytic particles, embedded in the silica substrates, are responsible for carbon agglomeration and subsequent tube axial growth, suggesting that nanotube alignment strongly depends upon the etching conditions (for example laser power, pulse duration, and focal distance). The pyrolysed products (usually nanotubes or nanofibres) were characterised by SEM, high-resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS) and energy dispersive X-ray spectroscopy (EDX). Samples containing only small amounts of amorphous carbon and other carbonaceous particles are notably absent. We observe that the degree of graphitisation is dependent upon the catalyst and the organic precursor. Interestingly, a nitrogen content З% was detected within the nanofibres, which exhibit corrugated graphite-like morphologies. This pyrolytic method may be used to advantage in generating aligned heteroatomic nanostructures such as BxCyNz systems. 相似文献
57Fe transmission Mössbauer at temperatures between 18 and 298 K and magnetic measurements have been used to characterize Fe-filled carbon nanotubes which were prepared by pyrolisis of Ferrocene + C60 at atmospheric pressure under an Ar atmosphere at 1050°C. The Mössbauer data have shown that the Fe phases encapsulated within the carbon nanotubes are -Fe, Fe3C and -Fe. The magnetic results are compatible with the Mössbauer data. Taken together the results allow us to propose a simple picture of the distribution of iron phases within the carbon nanotubes which would consist of an -Fe core surrounded by an -Fe shell, finally covered by an Fe3C layer. 相似文献
Perovskite‐like metal‐organic frameworks (MOFs) are hybrid materials of high interest for their potential in information storage technology, as Pb‐free substitutes for the widely used lead zirconate titanate (PZT) family of multiferroics. We report here a new, microwave‐assisted method of synthesis for perovskite‐like MOFs, which exploits the advantages of rapid and volumetric heating by microwaves in order to achieve synthesis within minutes, compared to days required by previously reported methods. The preliminary results demonstrate a broad control over the size and morphology of the products, by minor changes in the reaction conditions. An investigation of the effects of size and morphology on the magnetic and dielectric properties is presented here.
Electron impact excited 2Σ+ → 2Πi emission spectra of HCP+ and DCP+ have been observed. The spectra consist of short progressions in ν″3. The 0 000 → 0 010 bands have been studied under high resolution and rotational analyses carried out. Some of the more important derived constants are (in cm?1) HCP+; ν″3 = 1150(10), A″0 = -146.97(3), B″0 = 0.6224(16), B′0 = 0.6690(17); DCP+; ν″3 = 1110(10), A″0 = -146.71(1), B″0 = 0.5284(2), B′0 = 0.5682(2). 相似文献
The rotational spectrum of the new reactive triatomic molecule chloro(sulphido)boron, ClBS, produced by the high-temperature reaction of gaseous dichloro disulphide, Cl2S2, and crystalline boron at ca. 1000°C was studied by microwave spectroscopy between 26.5 and 40 GHz. Ground state rotational constants have been obtained for 11 of the 12 isotopic variants involving 35Cl, 37Cl, 11B, 10B, 32S, 33S, and 34S; the isotopic shifts for the ground state lines of 35Cl10B34S from those of 35Cl11B34S are too small and they are overlapped by the 11B species. The abundance of rotational constant data has allowed a detailed comparison of various structure determination procedures to be made. The substitution method yields an extremely consistent ClS distance of 3.28715 ± 0.00005 Å. Application of the first moment condition allows the B atom, which lies close to the center of mass, to be quite accurately located. The resulting bond lengths are and . The more important derived spectroscopic parameters are:
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