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  • 1
    Electronic Resource
    Electronic Resource
    Resolution of molecular polarizabilities of CH3–X and CH3–CH2–X derivatives into atomic terms (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 4053-4057 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: An additive scheme for resolving average molecular electric dipole polarizabilities into atomic contributions, based on the acceleration gauge for the electric dipole, has been applied to a series of methyl and ethyl derivatives, CH3–X and CH3–CH2–X. Extended calculations have been carried out to test the reliability of the partition method. Gross atomic isotropic contributions have been evaluated for carbon, hydrogen, and heteroatoms, showing a good degree of transferability from molecule to molecule. The theoretical values of atomic polarizabilities can be used to predict fairly accurate average polarizabilities of higher homologous molecules in the series of X-substituted alkanes. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1343902
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  • 2
    Electronic Resource
    Electronic Resource
    Shielding polarizabilities via continuous transformation of the origin of the current density in the set of small molecules: H2O2, F2, H2C2, H2CO, NH3, HCN, and HNC (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 6141-6151 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A procedure, based on a continuous transformation of the origin of the (quantum mechanical) current density that sets the diamagnetic contribution to zero (CTOCD-DZ ) all over the molecular domain, is applied to determine shielding polarizabilities to first order in a perturbing electric field. In any calculations relying on the algebraic approximation, irrespective of size and quality of the (gaugeless) basis set employed, all the components of the CTOCD-DZ magnetic shielding polarizability are origin independent, and the constraints for charge and current conservation are exactly satisfied. The effects of a static uniform electric field on the nuclear magnetic resonance (NMR) shielding of H2O2, F2, H2C2, H2CO, NH3, HCN, and HNC molecules have been investigated within the CTOCD-DZ method, and compared with the conventional results evaluated via the same basis sets, and with theoretical results taken from the literature. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.481215
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  • 3
    Electronic Resource
    Electronic Resource
    Ab initio calculation of atomic contributions to the magnetic susceptibility by continuous transformation of the origin of the current density in HF, H2O, NH3, and CH4 molecules (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 10706-10714 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The conventional random phase approximation (RPA) of the polarization propagator theory and a computational method based on continuous transformation of origin for the current density (CTOCD) induced within the electron cloud by an external homogeneous, static magnetic field has been employed to calculate atomic contributions to magnetic susceptibilities. The diamagnetic part of the magnetic susceptibility is written in terms of the polarization propagator. Since the paramagnetic term may also be obtained from the propagator it is thus possible to compute both contributions at the same level of approximation. The evaluated average susceptibility is independent of the origin of the vector potential, but depends on the origin of the reference frame. The atomic contributions to the diamagnetic and paramagnetic parts of the magnetic susceptibility are derived by applying off-diagonal hypervirial relations which are exactly fulfilled if the state functions are exact eigenfunctions of a model Hamiltonian. The rationalization of the magnetic susceptibilities into atomic contributions is applied to some small molecules: HF, H2O, NH3 and CH4, and the sum of these contributions is compared to the corresponding calculated total values and the experimental data for the molecular magnetic susceptibility for the same compounds. Computations are performed using basis sets of increasing quality. A series of sum rules for gauge independence of the computed results and charge-current conservation have been tested to document the accuracy of the calculation of magnetic properties. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.478040
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  • 4
    Electronic Resource
    Electronic Resource
    Resolution of alkane molecular polarizabilities into atomic terms (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 2987-2993 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Two additive schemes for resolving average molecular electric dipole polarizabilities into atomic contributions, based on the acceleration gauge for the electric dipole, are outlined. Extended calculations have been carried out for a few terms of the alkane series to test the reliability of the partition method. Gross atomic isotropic contributions evaluated for carbon, αAvC(approximate)5.7 a.u., and hydrogen, αAvH(approximate)2.7 a.u., are actually transferable from molecule to molecule, and can be used to predict fairly accurate average polarizabilities of higher homologous molecules in the alkane series. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.476890
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  • 5
    Electronic Resource
    Electronic Resource
    Conditions for invariance of molecular magnetic properties in Landau gauge transformations (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 1852-1859 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: General constraints for invariance of magnetic properties in a gauge transformation are analyzed. Sum rules relative to the transformation from Coulomb to Landau gauges are examined in particular. Numerical tests for hydrogen fluoride, water, ammonia, and methane molecule have been carried out in large basis set calculations, using random-phase approximation. The conditions for invariance are severe conditions for accuracy of variational molecular wave functions. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.469709
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  • 6
    Electronic Resource
    Electronic Resource
    Theoretical study of magnetic properties of ammonia molecule in nonuniform magnetic field (1996)
    Springer
    Theoretical chemistry accounts 94 (1996), S. 155-176 
    Details
    ISSN: 1432-2234
    Keywords: Nonuniform magnetic field ; Magnetic multipoles ; Magnetic susceptibility ; Nuclear magnetic shielding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The interaction Hamiltonian within the Bloch gauge for the potentials of the electromagnetic field has been used to define magnetic multipole moment operators and operators for the magnetic field of electrons acting on the nuclei of a molecule in the presence of nonhomogeneous external magnetic field. Perturbation theory has been applied to evaluate the induced electronic moments and magnetic field at the nuclei. Multipole magnetic susceptibility and nuclear magnetic shielding tensors have been introduced to describe the contributions arising in nonuniform fields, and their origin dependence has been analyzed. Extended numerical tests on the ammonia molecule in a static, nonuniform magnetic field have been carried out, using the random-phase approximation within the framework of accurate Hartree-Fock zero-order wavefunctions, and allowing for both angular momentum and torque formalisms in the calculation of paramagnetic contributions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00191646
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  • 7
    Electronic Resource
    Electronic Resource
    A measurement of the ratio of the nucleon structure function in copper and deuterium (1993)
    Springer
    The European physical journal 57 (1993), S. 211-218 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Results are presented on the ratios of the nucleon structure function in copper to deuterium from two separate experiments. The data confirm that the nucleon structure function,F 2, is different for bound nucleons than for the quasi-free ones in the deuteron. The redistribution in the fraction of the nucleon's momentum carried by quarks is investigated and it is found that the data are compatible with no integral loss of quark momenta due to nuclear effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01565050
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  • 8
    Electronic Resource
    Electronic Resource
    Exclusive ρ0 and Φ production in deep inelastic muon scattering (1988)
    Springer
    The European physical journal 39 (1988), S. 169-175 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Data are presented on exclusive ρ0 and ϕ production in deep inelastic muon scattering from a target consisting mainly of nitrogen. The ratio of the total cross sections for ρ0 and ϕ production is found to be 9∶(1.6±0.4) at 〈Q 2〉=7.5 GeV2, consistent with theSU(3) prediction of 9∶2. Thet dependence for exclusive ρ0 production is found to become shallover asQ 2 increases and, for largeQ 2, thet dependence is typical of that for a hard scattering process. Furthermore, the ratio of the cross sections for coherent: incoherent production from nitrogen is found to decrease rapidly withQ 2. Such behaviour indicates that even for exclusive vector meson production the virtual photon behaves predominantly as an electromagnetic probe.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01550991
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  • 9
    Electronic Resource
    Electronic Resource
    Forward produced hadrons in μp and μd scattering and investigation of the charge structure of the nucleon (1991)
    Springer
    The European physical journal 52 (1991), S. 361-387 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Final data measured with the EMC forward spectrometer are presented on the production of forward charged hadrons in μp and μd scattering at incident beam energies between 100 and 280 GeV. The large statistic of 373 000 events allows a study of the semi-inclusive hadron production as a function ofz,p T 2 and 〈p T 2 〉 in smallQ 2,x Bj andW bins. Charge multiplicity ratios and differences as a function ofz andx Bj are given forp, d andn-targets. From the differences of charge multiplicities the ratio of the valence quark distributions of the protond v (x)/u v (x) is determined for the first time in charged lepton scattering. The Gronau et al. sum rule is tested, the measured sum being 0.31±0.06 stat. ±0.05 syst., compared with the theoretical expectation of 2/7≈0.286. The measured sum corresponds to an absolute value of the ratio of thed andu quark charge of 0.44±0.10 stat.±0.08 syst.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01559431
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  • 10
    Electronic Resource
    Electronic Resource
    Comparison of forward hadrons produced in muon interactions on nuclear targets and deuterium (1991)
    Springer
    The European physical journal 52 (1991), S. 1-11 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Differential multiplicities of forward produced hadrons in deep inelastic muon scattering on nuclear targets have been compared with those from deuterium. The ratios are observed to increase towards unity as the virtual photon energy increases with no significant dependence on the other muon kinematic variables. The hadron transverse momentum distribution is observed to be broadened in nuclear targets. The dependence on the remaining hadron variables is investigated and the results are discussed in the framework of intranuclear interaction models and in the context of the EMC effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01412322
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