首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Pure monomeric urea molecules, free of contamination with decomposition products, have been obtained by sublimation of solid urea at ca 30°C and isolating in argon at ca 10K. Very high dilution is required to obtain the pure monomer which shows many spectral features different from that previously reported by King [Spectrochim. Acta28A, 165 (1972)]. The i.r. spectrum of the deutero-analogue has also been measured.  相似文献   

2.
Reaction of laser-ablated uranium with oxygen/fluorine mixtures or laser-ablated uranium dioxide ceramic with fluorine produces the uranium oxyfluorides molecules UO2F2, UO2F and UOF4, which have been isolated in solid argon and identified by virtue of the effects of oxygen isotopic substitution on their infrared spectra.  相似文献   

3.
Infrared spectra of anion radicals of tetracyanothiophene were recorded at −78°C. Large difference of the spectra was observed between the neutral molecule and the anion radicals and was interpreted by the change in the electronic structure.  相似文献   

4.
Summary The infrared spectra of a number of alkyl vinyl acetals were taken.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1721–1722, September, 1964  相似文献   

5.
6.
IR absorption spectra of As-Se glasses have been studied over a wide range of compositions. Various two-phonon, multiphonon (combination tones) and impurity absorptions have been identified. Compositional variation of relative band intensities has been explained in terms of the chemically ordered network model.  相似文献   

7.
The possible existence of geometrically isomeric forms of the title compound, CH3CBr2CH2CH3, has been investigated by i.r. spectroscopy. It was found that the general features of the spectra can be interpreted reasonably in terms of only one conformation of the molecules in the liquid state. Further confirmation of this view, based on a brief comparison of the liquid phase spectra of CH3CBr2CH2CH3 and CH3CHBrCHBrCH3 is given. Vibrational assignments have been made for most of the fundamental bands assuming Cs molecular symmetry.  相似文献   

8.
9.
Spectra of matrices with ethylene/argon ratios from 1/1 to 1/999 and a 1/24 ethylene/xenon matrix have been recorded in the temperature range 15–105 K. From relative i.r. intensities, frequency shifts and statistical calculations, the data are interpreted in terms of a monomer → dimer → aggregate → crystal scheme. It is proposed that the dimer, (C2H4)2, has D2d symmetry with a structure determined by quadruple hydrogen bonding and hydrogen-hydrogen repulsion. A method is described for calculation of the vibrational splitting due to interactions between the dimer molecular constituents.Solid ethylene has been studied between 15 and 85K. A transformation between two crystalline phases is characterized.  相似文献   

10.
Conclusions The IR spectra of seven trialkyl orthovanadates were studied. The absorption bands of the V=O and V-O bonds in the spectra of these compounds are found respectively in the 960–1012 and 600–662 cm–1 regions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2812–2814, December, 1972.  相似文献   

11.
12.
13.
14.
15.
Irradiation of a Ne matrix sample containing NO and CO near 4 K with an ArF excimer laser at 193 nm yielded new lines at 2045.1 and 968.0 cm(-1) that were depleted upon secondary photolysis at 308 nm. These lines are assigned to C=O stretching and mixed stretching modes of ONCO, based on results of 15N-, 13C-, and 18O-isotopic experiments and quantum-chemical calculations. These calculations using density-functional theory (B3LYP and PW91PW91/aug-cc-pVTZ) predict five stable isomers of NCO2: ONCO, NCOO, N-cyc-CO2, CNOO, and cyc-CNOO, listed in order of increasing energy. According to B3LYP calculations, ONCO has a trans configuration, with bond angles of angleONC approximately 136.3 degrees and angleNOC approximately 160.7 degrees. Calculated vibrational wave numbers, IR intensities, 15N-, 13C-, and 18O-isotopic shifts for ONCO agree satisfactorily with experimental results. ONCO was formed from reaction of CO with NO in its excited state.  相似文献   

16.
Neutral and anionic carbon clusters have been generated via a laser-induced graphite-based plasma and deposited in a solid argon matrix. Anionic clusters were formed from neutral clusters by using crossed electron/carbon cluster beams. Thermal annealing (to 36 K) resulted in the aggregation of the smaller carbon species, leading to the formation of long chain neutral and anionic clusters. Spectroscopic measurements in the ultraviolet, visible, near-infrared and infrared regions revealed a series of bands attributable to a homologous set of odd-numbered C5-C29 neutral clusters and even-numbered C6(-)-C36- anionic clusters. Good agreement is found for the band positions of carbon chains containing odd C15-C21 neutrals and even C6(-)-C22- anions, with species previously identified by Maier and coworkers using mass selection or laser vaporization, followed by neon matrix isolation. Resonance Raman frequencies for the neutral C17, C21 and C23 species are shown to be consistent with the above attributions. Density functional theory calculations agree well with the observed bands. It is found that certain low frequency Raman stretching frequencies decrease in a predictable way with increasing chain length. Comparison of the 0(0)0 absorption transitions of the even C18(-)-C36- anionic clusters with the 'unidentified' infrared (UIR) interstellar emission bands suggests that the electronic emission from specific long chain carbon anions may contribute to the some of the UIR bands.  相似文献   

17.
18.
19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号