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Full-Text Articles in Physics

A Hierarchical Family Of Three-Dimensional Potential Energy Surfaces For He-Co, Kirk A. Peterson, George C. Mcbane Aug 2005

A Hierarchical Family Of Three-Dimensional Potential Energy Surfaces For He-Co, Kirk A. Peterson, George C. Mcbane

Peer Reviewed Articles

A hierarchical family of five three-dimensional potential energy surfaces has been developed for the benchmark He-CO system. Four surfaces were obtained at the coupled cluster singles and doubles level of theory with a perturbational estimate of triple excitations, CCSD(T), and range in quality from the doubly augmented double-zeta basis set to the complete basis set (CBS) limit. The fifth corresponds to an approximate CCSDT/CBS surface (CCSD with iterative triples/CBS, denoted CBS+corr). The CBS limit results were obtained by pointwise basis set extrapolations of the individual counterpoise-corrected interaction energies. For each surface, over 1000 interaction energies were accurately interpolated using a …


Radiative Neutron Β-Decay In Effective Field Theory, Susan Gardner, Véronique Bernard, Ulf-G. Meißner, Chi Zhang Jul 2005

Radiative Neutron Β-Decay In Effective Field Theory, Susan Gardner, Véronique Bernard, Ulf-G. Meißner, Chi Zhang

Center for Plant Science Innovation: Faculty and Staff Publications

In summary, we have computed the photon energy spectrum and photon polarization in neutron radiative β-decay in an effective field theory approach, utilizing HBCHPT and the SSE, including all terms in O(1/M). The leading contribution to the photon energy spectrum has been calculated previously [4]; we agree with the expression in Ref. [4] for Σspins |M|2, though we disagree with their numerical results for the photon energy spectrum. Moreover, we find that the O(1/M) terms are numerically quite small, generating contributions no larger than O(0.5 %), so that radiative neutron β-decay is quite insensitive to nucleon structure …


Vibrational Dependence Of The H2–H2 C6 Coefficients, Robert Hinde Jan 2005

Vibrational Dependence Of The H2–H2 C6 Coefficients, Robert Hinde

Chemistry Publications and Other Works

We use the sum-over-states formalism to compute the imaginary-frequency dipole polarizabilities for H2, as a function of the H–H bond length, at the full configuration interaction level of theory using atom-centered d-aug-cc-pVQZ basis sets. From these polarizabilities, we obtain isotropic and anisotropic C6 dispersion coefficients for a pair of H2 molecules as functions of the two molecules’ bond lengths.


Anion And Cation-Yield Spectroscopy Of Core-Excited Sf6, Maria Novella Piancastelli, Wayne C. Stolte, Renaud Guillemin, A. Wolska, M. M. Sant'anna, Dennis W. Lindle Jan 2005

Anion And Cation-Yield Spectroscopy Of Core-Excited Sf6, Maria Novella Piancastelli, Wayne C. Stolte, Renaud Guillemin, A. Wolska, M. M. Sant'anna, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

We report an extensive study on total and partial-ion-yield spectroscopy around both the S 2p and F 1s thresholds in SF6. All positive and negative single-ion channels have been measured. Below the F 1s threshold we detect a large variation in relative intensity of the resonant structures according to the specific channel monitored, indicating selective fragmentation. Above threshold, at variance with previous cases described by us, we detect high-intensity structures related to shape resonances not only in the cation channels but also for the anions. We discuss the applicability and limits of a model we …


Fragmentation Dynamics Of H2s Following S 2p Photoexcitation, Renaud Guillemin, S-W Yu, Wayne C. Stolte, Dennis W. Lindle Jan 2005

Fragmentation Dynamics Of H2s Following S 2p Photoexcitation, Renaud Guillemin, S-W Yu, Wayne C. Stolte, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

The fragmentation dynamics of core-excited H2S has been studied by means of partial anion and cation yield measurements around the S L2,3-subshell ionization thresholds. All detectable ionic fragments are reported, and significant differences between partial ion yields are observed. Possible dissociation pathways are discussed by comparison to previous studies of electron spectra.


Near-Edge X-Ray Absorption Fine Structure Study Of Ion-Beam-Induced Phase Transformation In Gd2(Ti1-Yzry)2o7, Ponnusamy Nachimuthu, S. Thevuthasan, V. Shutthanandan, E. M. Adams, W. J. Weber, B. D. Begg, D. K. Shuh, Dennis W. Lindle, Eric M. Gullikson, Rupert C. Perera Jan 2005

Near-Edge X-Ray Absorption Fine Structure Study Of Ion-Beam-Induced Phase Transformation In Gd2(Ti1-Yzry)2o7, Ponnusamy Nachimuthu, S. Thevuthasan, V. Shutthanandan, E. M. Adams, W. J. Weber, B. D. Begg, D. K. Shuh, Dennis W. Lindle, Eric M. Gullikson, Rupert C. Perera

Chemistry and Biochemistry Faculty Research

The structural and electronic properties of Gd2(Ti1−yZry)2O7 (y=0–1) pyrochlores following a 2.0-MeV Au2+ ion-beam irradiation (~5.0 X 1014 Au2+/cm2) have been investigated by Ti 2p and O 1s near-edge x-ray absorption fine structure (NEXAFS). The irradiation of Gd2(Ti1−yZry)2O7 leads to the phase transformation from the ordered pyrochlore structure (Fd3m) to the defect fluorite structure (Fm3m) regardless of Zr concentration. Irradiated Gd2(Ti1−y …