The IR spectra of trans-1,4-chlorobromo- and trans-1,4-chloroiodocyclohexane were recorded in the region 4000–30 cm−1 as solutes in various solvents, as KI and polyethylene pellets and as solids under high pressure (1–50 kbar at ambient temperature). Additional spectra of the melts, amorphous and annealed crystalline solids at 90 K and dichroism of oriented polycrystalline films were obtained above 200 cm−1. Raman spectra of the compounds were recorded in the amorphous and crystalline states at 90 K, and polarization measurements were made in CCl4 CS2 and C6H6 solution.

A new force field is developed for the in-plane vibrations of condensed aromatics using pyrene as a test molecule. Only five parameters are employed in this force field, which improves a four- parameter approximation previously investigated. Still the simple five-parameter approximation gives calculated vibrational frequencies in good agreement with those from the more elaborate Califano-Neto force field. In the course of the normal coordinate analysis the Hüekel molecular orbitals have been de­duced. The CC stretching parameters were modified by means of the calculated bond orders. A complete set of independent symmetry coordinates (both in-plane and out-of-plane) for the pyrene molecular model was developed. New experimental data from infrared and Raman spectra for pyrene are reported. Also the mean amplitudes of vibration are studied in detail. It is concluded that the simple five-parameter approximation gives reliable mean amplitudes, which undoubtedly are accurate enough for the interpretation of gas electron diffraction data. Finally the calculated frequencies and mean amplitudes of benzene are given. The mean amplitudes are again found to be very accurate in spite of some substantial inaccuracies in the frequencies.

Chemischer InformationsdienstVolume 10, Issue 42 Physical Organic Chemistry ChemInform Abstract: CONDENSED AROMATICS. PART III. IN-PLANE MOLECULAR VIBRATIONS OF PYRENE S. J. CYVIN, S. J. CYVINSearch for more papers by this authorB. N. CYVIN, B. N. CYVINSearch for more papers by this authorJ. BRUNVOLL, J. BRUNVOLLSearch for more papers by this authorJ. C. WHITMER, J. C. WHITMERSearch for more papers by this authorP. KLAEBOE, P. KLAEBOESearch for more papers by this authorJ. E. GUSTAVSEN, J. E. GUSTAVSENSearch for more papers by this author S. J. CYVIN, S. J. CYVINSearch for more papers by this authorB. N. CYVIN, B. N. CYVINSearch for more papers by this authorJ. BRUNVOLL, J. BRUNVOLLSearch for more papers by this authorJ. C. WHITMER, J. C. WHITMERSearch for more papers by this authorP. KLAEBOE, P. KLAEBOESearch for more papers by this authorJ. E. GUSTAVSEN, J. E. GUSTAVSENSearch for more papers by this author First published: October 16, 1979 https://doi.org/10.1002/chin.197942050AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume10, Issue42October 16, 1979 RelatedInformation

Chemischer InformationsdienstVolume 10, Issue 8 Physical Organic Chemistry ChemInform Abstract: SUBSTITUTED PROPANES. PART XIV. THE LOW FREQUENCY VIBRATIONS OF 1,3-DICHLORO-, 1,3-DIBROMO-, 1,2,3-TRICHLORO- AND 1,2,3-TRIBROMOPROPANE J. E. GUSTAVSEN, J. E. GUSTAVSENSearch for more papers by this authorP. KLAEBOE, P. KLAEBOESearch for more papers by this authorR. STOELEVIK, R. STOELEVIKSearch for more papers by this author J. E. GUSTAVSEN, J. E. GUSTAVSENSearch for more papers by this authorP. KLAEBOE, P. KLAEBOESearch for more papers by this authorR. STOELEVIK, R. STOELEVIKSearch for more papers by this author First published: February 20, 1979 https://doi.org/10.1002/chin.197908047AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. References J. E. GUSTAVSEN, P. KLAEBOE, R. STOELEVIK, SUBSTITUTED PROPANES. PART XIV. THE LOW FREQUENCY VIBRATIONS OF 1,3-DICHLORO-, 1,3-DIBROMO-, 1,2,3-TRICHLORO- AND 1,2,3-TRIBROMOPROPANE, J. Mol. Struct., 1978, 50, 285. DOI: 10.1016/0022-2860(78)80087-8; 10.1016/0022-2860(78)80087-8 CASWeb of Science®Google Scholar Volume10, Issue8February 20, 1979 ReferencesRelatedInformation

Infrared spectra of 1,2-dicyanotetrafluoroethane have been recorded in the vapour, glassy solid, and crystalline solid states. Raman spectra have been recorded of the liquid and the crystalline solid. The trans form is shown to exist alone in the crystal, while trans and gauche forms co-exist in the vapour, liquid and in the amorphous solid with the trans conformer dominating.

Abstract An approximate force field for the in-plane vibrations of condensed aromatics with only five parameters is investigated. Calculated frequencies are given for naphthalene, anthracene and coronene. The results are compared with values from other, more elaborate methods, mainly the Califano-Neto force field. The five-parameter approximation is found to be useful as an aid in assignments of experimental frequencies. It appears to give amazingly good results considering its great simplicity and small number of parameters. New experimental infrared and Raman data for anthracene and coronene are given. Especially some new features in the Raman spectrum of anthracene are reported in some details.

AbstractRaman spectra of 1,2‐diiodotetrafluoroethane in the liquid and solid states as well as far infrared spectra of the vapour and of a benzene solution have been obtained. These data complement earlier infrared spectra. The compound is shown to exist in the trans conformation in the crystal and as a mixture of trans and gauche conformers in the other phases. Vibrational assignments are made, aided by normal coordinate calculations.

The far-IR and Raman spectra of 1,3-dichloro-, 1,3-dibromo-, 1,2,3-trichloro- and 1,2,3-tribromopropane were reinvestigated in solution and in the liquid state in the region 300-30 cm−1. Additional IR and Raman bands were observed, revealing that the compounds had fundamentals below 80 cm−1 attributed to torsional modes. Earlier discrepancies between the torsional modes predicted from electron diffraction measurements and spectral data have been removed.