Accession Number : AD0645777

Title :   THE MICROWAVE SPECTRUM OF PIVALALDEHYDE,

Corporate Author : HARVARD UNIV CAMBRIDGE MASS DEPT OF CHEMISTRY

Personal Author(s) : Ronn,A. M. ; Woods,R. C.

Report Date : 14 JUL 1966

Pagination or Media Count : 28

Abstract : The microwave spectrum of pivalaldehyde ((CH3)3CCHO) was investigated in the frequency region 9-40 kMc/sec. The ground state, first and second excited states of the t-butyl torsion, and the first excited state of each of the three methyl torsions were assigned. The barrier to internal rotation of the t-butyl top was calculated from the splittings in the first excited state to be 1186 cal/mole, from the splittings in the second excited state to be 1176 cal/mole, and from the intensities of the first excited state relative to the ground state to be 1100 cal/mole. The excited states of the methyl torsions show no splittings, but the relative intensities yield barrier estimates of 2600 cal/mole, 3500 cal/mole, and 3800 cal/mole, if one assumes that the three tops are independent. On the basis of certain analogies with previously investigated molecules the lowest of these barriers is very tentatively assigned to a methyl group which is eclipsed with respect to the oxygen atom. The dipole moment components were computed from Stark effect measurements to be mu-a = 2.56 D and mu-b = 0.76 D. (Author)

Descriptors :   (*MICROWAVE SPECTROSCOPY, *ALDEHYDES), (*MOLECULAR ENERGY LEVELS, ALDEHYDES), GROUND STATE, EXCITATION, CHEMICAL BONDS, ROTATION, THERMOCHEMISTRY, DIPOLE MOMENTS, STARK EFFECT

Subject Categories : Organic Chemistry
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE