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  • 1
    Electronic Resource
    Electronic Resource
    An experimental and theoretical study of the deuterium quadrupole coupling constants of glycine (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 82 (1985), S. 3516-3526 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.448931
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Molecular electron density distributions in position and momentum space (1985)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 89 (1985), S. 969-974 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100252a016
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  • 3
    Electronic Resource
    Electronic Resource
    Porphyrins 42. Ground and excited state calculations on the isomers of free base porphine and sirohydrochlorin (1982)
    Springer
    Theoretical chemistry accounts 61 (1982), S. 227-241 
    Details
    ISSN: 1432-2234
    Keywords: Sirohydrochlorin ; Isobacteriochlorin ; Porphine ; Porphyrins ; MINDO/3 ; INDO/S/CI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Symmetry instabilities were encountered during MINDO/3 geometry optimizations of the sirohydrochlorin and porphine isomers leading to bond alternating optimal structures. Transition energies and oscillator strengths were calculated with INDO/S/CI. Our calculations predict the ground state cis and trans isomers of sirohydrochlorin to be close in energy and confirm the experimental assignment of the absorptions bands, with the cis tautomer having a red shifted spectrum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00550968
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  • 4
    Electronic Resource
    Electronic Resource
    Theoretical invstigations of the electronic states of porphyrins. I. Basis set development and predicted spectrum of pyrrole (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 237-250 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new minimum basis set was developed for use in computing excitation energies of large molecules. It is particularly suited to calculating ionization potentials and Rydberg transitions. Pyrrole excitation energies and oscillator strengths calculated with this basis set are compared to larger basis set ab initio and semiempirical results. The 6-eV band in the experimental spectrum is predicted to be the result of three Rydberg absorptions, with no underlying (π, π*) absorption. The calculations also provide an explanation for the observed N—H stretch in the 6-eV region.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260209
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  • 5
    Electronic Resource
    Electronic Resource
    Theoretical investigations of the electronic states of porphyrins. III. Low-lying electronic states of porphinatoiron(II) (1985)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 28 (1985), S. 773-796 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio configuration interaction calculations are reported on the lowest quintet, triplet, and singlet states of FeII(P). Due to the large number of states found, a catalog of the low-lying states is presented. Novel triplet and quintet charge-transfer states are reported as low as 1.3 eV. These states are d5 (S = 5/2) on the iron low-spin-coupled to the radical anion excited porphyrin ring (S = 1/2 or 3/2). Oscillator strengths originating from each of three low-energy triplet states are reported.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560280611
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  • 6
    Electronic Resource
    Electronic Resource
    Theoretical investigations of the electronic states of porphyrins. II. Normal and hyper phosphorus porphyrins (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 251-274 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio methods have been used to calculate the ground and excited states of “normal” and “hyper” porphyrins. Perturbation theory and CI methods were used to determine differential ground and excited-state correlation effects for [Pv(P)F2]+ and [PIII(P)]+. A comparison is made to the INDO/S/CI predicted wavefunctions and spectra and to the experimental spectra of closely related molecules. The “hyper” [PIII(P)]+ calculations show some very low energy electronic transitions which provide an explanation for an anomalous “red” band in the spectrum and for the lack of fluorescence. Ab initio calculations also predict that (1) the lowest energy 1A1 state is a two-configuration wavefunction which can be described as a diradical, (2) the two lowest-energy singlet excited states are double excitations from the closed shell SCF configuration, and (3) a 3B2 state is very close in energy to the lowest 1A1 state.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260210
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    Paper (German National Licenses)
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