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1.
In the IR absorption spectra of low-temperature molecular liquids, we have observed anomalously large isotope shifts of frequencies of vibrational bands that are strong in the dipole absorption. The same effect has also been observed in their Raman spectra. At the same time, in the spectra of cryosolutions, the isotope shifts of the same bands coincide with a high accuracy (±(0.1–0.5) cm–1) with the shifts that are observed in the spectra of the gas phase. The difference between the spectra of examined low-temperature systems is caused by the occurrence of resonant dipole–dipole interactions between spectrally active identical molecules. The calculation of the band contour in the spectrum of liquid freon that we have performed in this work taking into account the resonant interaction between states of simultaneous transitions in isotopically substituted molecules can explain this effect.  相似文献   
2.
Mid-infrared spectra of mixed solutions in liquid xenon containing fluoroform and either ammonia or pyridine have been investigated at temperatures between 173 and 213 K. For both Lewis bases, a new band is found in the CH stretching region at a frequency approximately 5 cm(-1) higher than that of monomer fluoroform, which is assigned to a complex between fluoroform and the Lewis base. A detailed analysis of the nu1/2nu(4) Fermi resonance in the proton donor shows that the blue shifts observed for the complexes are not caused by a strengthening of the CH bond during the complexation, but are due to the changes in the Fermi resonance interactions. Information on the nu1/2nu(4) Fermi resonance was also obtained for the complexes of fluoroform with dimethyl ether and trimethyl amine.  相似文献   
3.
Experiments on the search for the effect of resonant screening on the Mössbauer absorption of 119m Sn γ rays of energy 23.8 keV emitted by a standard Mössbauer Ca119m SnO3 γ source in the resonant SnO2 absorber of natural isotopic composition are described. Intensities of tin γ rays and X-rays that passed through the absorber were measured with and without a resonant cylindrical screen (which was a black absorber for the 23.8-keV Mössbauer γ line) around the absorber and their ratios were calculated for each radiation separately. No difference beyond the experimental error was found between these ratios measured with the γ source both at rest and when oscillating with a frequency and amplitude enough to completely break the conditions for Mössbauer resonant absorption of 23.8-keV γ rays. The upper limit for the relative decrease, due to the influence of the resonant screen, in the intensities of these γ rays after their passing through the resonant absorber was 0.00030.  相似文献   
4.
IR absorption spectra of monoisotopic 28SiH4 and 76GeH4 are studied in Ar and N2 matrices at 10 K. It is shown that the absorption spectra of silane and germane are similar in the regions of the stretching ν3 and bending ν4 vibrations. Four groups of bands can be separated out in the spectra of each molecule: (1) narrow bands characteristic of the matrix isolation studies, (2) broad bands, (3) diffuse absorption with a large value of the spectral moment M 2* the intensity of which increases upon annealing, and (4) bands of dimers the intensity of which increases quadratically with concentration. The spectra of 28SiH4 and 76GeH4 in nitrogen matrices contain a triplet in the stretching region and a doublet in the bending region, which is explained by the change in the molecular symmetry from T d to C 3V on passage from the gas phase to solid nitrogen.  相似文献   
5.
6.
Melikova  S. M.  Rutkowski  K. S.  Shchepkin  D. N.  Macholl  S.  Herrebout  W. 《Optics and Spectroscopy》2021,129(10):1130-1137
Optics and Spectroscopy - The sequences of Fermi resonances νs ≈ 2νb in the IR spectrum of a fluoroform solution (CHF3) in liquefied krypton have been studied. Here, νs is the...  相似文献   
7.
The model of an anisotropic, layerlike medium is often employed in problems of electromagnetic probing, and many papers have been written on the propagation of an electromagnetic field in such media. A systematic exposition of such problems was set out by Tikhonov, Sku-garevskaya, and Dmitriev [1–6]. In this paper we shall construct an asymptotic for the electromagnetic field of a point source lying above a layerlike medium of finite anisotropy having a fairly high longitudinal and transverse conductivity, or in which the source lies at a considerable height above the medium. The principles here laid down for the construction of the asymptotic indicate quite clearly under what circumstances the asymptotic is feasible, and if necessary allow the next approximations to be taken into account.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 2, pp. 175–188, March–April, 1966.  相似文献   
8.
We have studied the IR absorption spectra of diluted mixtures SiF4/M = 1/6000–1/10 000 in an N2 matrix at 11 K (for comparison, the spectra of SiF4 in Ar and Xe matrices have also been studied). It has been shown that, in solid nitrogen, the appearance of doublets is observed both in the range of the ν3 band of the SiF4 (28SiF, 29SiF4, and 30SiF4) isotopologues of the SiF4 molecule and in the range of the ν1 + ν4, ν2 + ν3, and ν1 + ν3 bands of 28SiF4, whereas, in the range of the 2ν3 band of 28SiF, a triplet appears. In order to analyze the influence of the matrix on the spectrum of free SiF4 molecules, we have used a model that makes it possible to successively calculate (i) the spectrum of SiF4 in terms of the model of local modes, (ii) the structure of a matrix composed by 864 N2 molecules + a rigid SiF4 molecule using the Monte Carlo method, and (iii) the interaction of matrix particles with local dipole moments in the approximation of dipole-induced dipole and dipole-quadrupole interactions. The model describes satisfactorily the low-frequency shift of bands in the nitrogen matrix. All obtained experimental and theoretical results are consistent with the assumption that two kinds of stable trapping centers of SiF4 molecules obeying the T d symmetry are realized in the nitrogen matrix.  相似文献   
9.
We investigate the IR spectra of solutions of R-21,-22,-116, and R-218 in liquid argon at 90K. The frequencies, half-widths, and absolute integral intensities of all of the absorption bands recorded are obtained and interpreted. Scientific-Research Institute of Physics, 1, Ul'yanovskaya Str., Petrodvorets, St. Petersburg, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 297–301, May–June, 1997.  相似文献   
10.
The band shape theory of the vibrational transitions accompanied by an excitation of a strongly IR-active fundamental is elaborated for low-temperature molecular liquids with an account for strong intermolecular resonance dipole–dipole interactions. The developed model of a liquid uses the regular (fcc structure) crystal whose structure is then destroyed by introducing random, normally distributed displacements of particle positions, by assigning arbitrary molecular orientations as well as a varied number of randomly distributed vacancies. This model was applied to several molecular liquids , those having triply degenerate modes were studied more in detail.  相似文献   
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