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Full-Text Articles in Physics

Structure And Stability Of The Alx And Alx- Species, Gennady L. Gutsev, Puru Jena, Rodney J. Bartlett Jan 1999

Structure And Stability Of The Alx And Alx- Species, Gennady L. Gutsev, Puru Jena, Rodney J. Bartlett

Physics Publications

The electronic and geometrical structures of the ground and low-lying excited states of the diatomic AlX and AlX− series (X=H, Li, Be, B, C, N, O, and F) are calculated by the coupled-cluster method with all singles and doubles and noniterative inclusion of triples using a large atomic natural orbital basis. All the ground-state AlX molecules except for AlF can attach an additional electron and form ground-state AlX− anions. The ground-state AlBe−, AlB−, AlC−, AlN−, and AlO− anions possess excited states that are stable toward autodetachment of an extra electron; AlBe− also has a second excited state. Low-lying excited states …


Does N-2(-) Exist? A Coupled-Cluster Study, Gennady L. Gutsev, Piotr B. Rozyczko, Rodney J. Bartlett, Charles A. Weatherford Jan 1999

Does N-2(-) Exist? A Coupled-Cluster Study, Gennady L. Gutsev, Piotr B. Rozyczko, Rodney J. Bartlett, Charles A. Weatherford

Physics Publications

Potential energy curves of the ground-state N2 molecule and its doublet N−2 anion are calculated at the coupled-cluster level with single and double excitations and with noniterative triples [CCSD(T)] as well as with the multireference averaged-quadratic coupled-cluster (MR-AQCC) method. The N−2 anion is shown to be temporary and decays to its neutral parent plus a free electron at bond lengths shorter than ≈1.4 and larger than ≈2.5 Å. Thus, the N−2 anion exists within the 1.4⩽R(N–N)⩽2.5 Å range at the Born–Oppenheimer approximation.


Evolution Of The Electronic Structure And Properties Of Neutral And Charged Aluminum Clusters: A Comprehensive Analysis, B. K. Rao, P. Jena Jan 1999

Evolution Of The Electronic Structure And Properties Of Neutral And Charged Aluminum Clusters: A Comprehensive Analysis, B. K. Rao, P. Jena

Physics Publications

Density-functional theory with generalized gradient approximation for the exchange-correlation potential has been used to calculate the global equilibrium geometries and electronic structure of neutral, cationic, and anionic aluminumclusters containing up to 15 atoms. The total energies of these clusters are then used to study the evolution of their binding energy, relative stability, fragmentation channels, ionization potential, and vertical and adiabatic electron affinities as a function of size. The geometries are found to undergo a structural change from two dimensional to three dimensional when the cluster contains 6 atoms. An interior atom emerges only when clusters contain 11 or more atoms. …


Search For “Quadrupole-Bound” Anions. I, Gennady L. Gutsev, Puru Jena, Rodney J. Bartlett Jan 1999

Search For “Quadrupole-Bound” Anions. I, Gennady L. Gutsev, Puru Jena, Rodney J. Bartlett

Physics Publications

In a classical model, some anions exist due to the attraction between an electron and a molecule’s dipole moment. When the dipole moment is sufficiently large (μcrit>2.5 D), an electron can be trapped. Can a sufficiently large quadrupole moment produce the same effect? To help answer this question, we can search for molecules with a large quadrupole moment and use predictive, ab initio, correlated quantum chemistry methods to assess whether an anion forms and, if it does, to discover its nature. For this purpose, coupled-cluster calculations are reported for the structure and properties of KnClm and KnCl−m (n,m=0–2). …


Thermodynamical Stability Of Ch3ono And Ch3ono-: A Coupled-Cluster And Hartree-Fock-Density-Functional-Theory Study, Gennady L. Gutsev, Puru Jena, Rodney J. Bartlett Jan 1999

Thermodynamical Stability Of Ch3ono And Ch3ono-: A Coupled-Cluster And Hartree-Fock-Density-Functional-Theory Study, Gennady L. Gutsev, Puru Jena, Rodney J. Bartlett

Physics Publications

The structure and thermodynamic stability of methylnitrite and its anion are studied by the infinite-order coupled-cluster method with all singles and doubles and noniterative inclusion of triple excitations [CCSD(T)] and Hartree–Fock-density-functional theory (HFDFT). We have optimized the geometries and computed the harmonic vibrational frequencies of major fragments, H2, CH, NH, OH, CN, N2, CO, NO, O2, CH2, NH2, H2O, HCN, HNC, HCO, HNO, O2H, CO2, NO2, CH3, NH3, CNH2, HCO2, HNO2, CH3N, CH3O, CH3NO, CH3ON, CH2NO2, and their anions, when the latter exist. Fragmentation energies obtained at both levels of theory are rather close to each other, except for channels …