Accession Number : AD0675272

Title :   SPECTROSCOPIC INVESTIGATION OF THE STRUCTURES OF THE CRYSTALLINE PHASES OF ACETYLENE.

Descriptive Note : Technical rept.,

Corporate Author : MICHIGAN STATE UNIV EAST LANSING DEPT OF CHEMISTRY

Personal Author(s) : Smith,William Hayden ; Leroi,George E.

Report Date : SEP 1968

Pagination or Media Count : 26

Abstract : Infrared and Raman spectra of both crystalline phases of C2H2 and C2D2 were obtained. The Raman spectrum of liquid C2H2 was also observed. The spectra of the low temperature phase are interpreted as arising from an orthorhombic crystal with a D2h space group having two molecules per unit cell on C2h sites. The molecular axes are shown to be oriented perpendicular to the C2 axis at the site. The spectroscopic observations in the high temperature phase are in very close agreement with predictions based upon the x-ray determined Th(6) cubic space group with four molecules per unit cell on S6 sites. An approximate calculation of the lattice frequencies in this phase is in reasonable agreement with observation. Changes in intensities of some fundamentals with phase are qualitatively related to intermolecular hydrogen bonding. (Author)

Descriptors :   (*ALKYNES, CRYSTAL STRUCTURE), (*SOLIDIFIED GASES, *CRYSTAL STRUCTURE), INFRARED SPECTROSCOPY, RAMAN SPECTROSCOPY, LIQUEFIED GASES, PHASE STUDIES, CRYSTAL LATTICES, MOLECULAR ASSOCIATION

Subject Categories : Crystallography
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE