Search

The nature of the inhomogeneous broadening of optical and ODMR spectral lines of aromatic molecules hosted in low temperature glasses is experimentally and theoretically investigated. Particular attention is paid to the relationships which exist between the various classes of inhomogeneously broadened spectral lines, and the salient features are illustrated with the results of ‘‘site selection’’ spectroscopy. A theoretical formalism based on the assumption of a uniform ‘‘solvent field’’ is presented and used to account for the major experimental features. Various ODMR line broadening mechanisms are considered and their relative importance evaluated. [ABSTRACT FROM AUTHOR]

Single crystals of α-glycine with two, three, and five of the protons replaced by deuterium are studied at 4.2 K using electron–nuclear double resonance (ENDOR) spectroscopy to detect the NMR transitions of the distant deuterons on diamagnetic molecules. Complete deuteron quadrupole interaction tensors, and indirectly the electric field gradient tensors, are determined for all the labeled positions. Proton dipolar coupling tensors are also obtained for the methylene hydrogens in the case of glycine-d3. The relationship between the deuterium quadrupole coupling constants and the inverse cube of the bond length is refined and discussed. The resulting structural information including X–D bond lengths and bond angles is compared with data obtained by neutron diffraction. In addition, extensive calculations at both the semiempirical and ab initio levels are carried out to determine the electric field gradient at the hydrogen positions. Both intramolecular and lattice contributions are considered. [ABSTRACT FROM AUTHOR]

Presents the contribution of chemist Ernest Roy Davidson on chemistry in the United States. Efforts of Davidson on the emission-excitation matrices of the multicomponent fluorescence data; Invention of the rank annihilation concept in the field of analytical chemistry; Calculations of zero-field splitting in the triplet states of porphyrins.