### RADIATION DAMAGE IN ORGANIC CRYSTALS. I. CH(COOH)$sub 2$ IN MALONIC ACIDRADIATION DAMAGE IN ORGANIC CRYSTALS. I. CH(COOH)$sub 2$ IN MALONIC ACID

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 Author McConnell, H. M. ♦ Heller, C. ♦ Cole, T. ♦ Fessenden, R. W. Sponsorship USDOE Source United States Department of Energy Office of Scientific and Technical Information Content type Text Language English
 Subject Keyword CHEMISTRY ♦ ATOMS ♦ CARBON ♦ CRYSTALS ♦ DECOMPOSITION ♦ ELECTRONS ♦ FREE RADICALS ♦ HYDROGEN ♦ INTERACTIONS ♦ LATTICES ♦ MAGNETIC RESONANCE ♦ ORGANIC ACIDS ♦ ORGANIC COMPOUNDS ♦ OXYGEN ♦ PROTONS ♦ RADIATIONS ♦ SPIN ♦ X RADIATION Abstract An analysis of the electron magnetic resonance of single crystals of malonic acid that were subjected to x-ray damage indicates that: (a) the principal long-lived paramagnetic species produced by the x-ray darnage is gen atoms of this radical are oriented in the crystalline lattice in the same way as these atoms are arranged in the parent undamaged malonic acid molecule. (c) The z,x,y components of the diagonal (electron-spin) - (nuclear-spin) coupling dyadic for the proton attached to the alpha -carbon atom are found to be of the same relative sign and of magnitudes 29. 61, and 91 Mc, respectively. In this orthogonal axis system, z is the CH bond direction and x is perpendicular to the plane of the three carbon atoms. These results are in excellent agreement with theoretical values of the distributed dipole and contact hyperfine interactions and show that this molecule is a pi -electron radical, that the unpaired electron is concentrated almost entirely on the alpha -carbon and that the spin density on the in-plane sigma -proton is negative. The observed g-factors for this radical are g/sub x/ = 2.0026, g/sub y/ = 2.0035, and g/sub z/ = 2.0033 and are in good qualitative agreement with previous theoretical estimates of these quantities. (auth) ISSN 00027863 Educational Use Research Learning Resource Type Article Publisher Date 1960-02-20 Publisher Department California Inst. of Tech., Pasadena Journal Journal of the American Chemical Society Volume Number 82 Organization California Inst. of Tech., Pasadena