Showing papers on "Infrared spectroscopy correlation table published in 1972"

Dynamics of Sodium and Potassium Bifluoride: Infrared, Raman, and Neutron Studies

Abstract: The crystal and molecular dynamics of NaHF2 and KHF2 have been studied by infrared and Raman spectroscopy and by neutron inelastic scattering. Infrared absorption spectra have been measured in the region of the bending (v2) and asymmetric stretching (v3) vibrations of NaHF2 and KHF2 containing 2%, 11%, and ≈ 80% DF2−. The spectra show a rather striking reduction in the widths of the DF2− absorption peaks as well as shifts in peak frequencies as the percent DF2− is lowered toward a ``defect'' concentration. These results indicate that the considerable width of the infrared absorption bands assigned to the v2 and v3 modes in pure NaHF2 and KHF2 is associated with the coupling of near‐neighbor HF2− oscillators having similar frequencies or energy states. The Raman spectrum for NaHF2 shows peaks at 630.5 and 145 cm−1 which can be unambiguously assigned, respectively, to the HF2− symmetric stretching mode (A1g) and the Eg librational lattice mode. The KHF2 Raman spectrum is similar to a previous result, with s...

Infrared Spectrum of Matrix Isolated NbF5

Abstract: The infrared spectra of matrix isolated NbF5 as well as some gas phase spectra have been observed. These spectra have been obtained using double boiler Knudsen cells. An interpretation of the spectra to yield the six infrared active frequencies of a C4v monomeric structure for NbF5 is advanced.

Infrared spectra of complex organic selenium compounds.

Abstract: The interpretation of the infrared spectra of complex organic compounds still has to be based to a large extent on the empirical concept of localized group frequencies, although complete vibrational assignments have been published for many of the simpler compounds. Great difficulties are encountered when we try to use the concept of group frequencies in the study of infrared spectra of sulfur and selenium compounds, for the stretching vibrations of carbon-sulfur and carbon-selenium bonds apparently couple with other vibrations to such an extent that it is difficult to identify a characteristic group frequency. This is especially true for compounds that contain sulfur or selenium incorporated in a welectron system, including the compounds that are formulated with a double bond from carbon to sulfur or selenium. The following is a review of work w r i e d out in this field in Chemical Laboratory 11 of the University of Copenhagen. It should be emphasized that until recently most of our work has been synthetic and only exploratory in regard to infrared spectroscopy because most of the selenium compounds studied have been new compounds. In addition to the usual aids to the interpretation of vibrational spectra-such as Raman spectroscopy, evaluation of line contours of the gas phase infrared spectra, and isotopic substitution, in particular deuteration-a further tool is available for the evaluation of the spectra of organic selenium compounds, namely, comparison with the spectra of corresponding sulfur compounds. The observation that the infrared spectra of certain dithiocarbonates and diselenocarbonates differ mainly in the position of a strong band, found at ca. 1050 cm-' in the spectra of the sulfur compounds and at ca. 100 cm-* lower wave number in the spectra of the selenium compounds, initiated extensive investigations on the use of the replacement of sulfur by selenium as a diagnostic probe in infrared spectroscopy.' The idea was that because of the great similarity in chemical properties between sulfur and selenium this exchange would mainly affect the vibrations of the sulfuror selenium-containing groups, leaving the remainder of the spectrum virtually unchanged. Accordingly, the replacement of sulfur by selenium or vice versa would be comparable to an isotopic substitution and could be used for analogous purposes. This substitution was briefly designated \" selenation,'*2 although the process, of course, cannot be carried Out directly. The question whether the assumption that selenation would show the characteristics of an isotopic substitution was warranted will be discussed later.

Infrared spectra of polyurethanes in the near infrared region

Abstract: 9 I974 Consultants Bureau, a division of Plenum Publishing Corporation, 227 F('est 17th Street, New York, N. Y. 10011. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, eleqtronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission of the publisher. A copy of this article is available from the publisher for $15.00.