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Full-Text Articles in Atomic, Molecular and Optical Physics

Low-Energy Electron Capture By 6-Aza-2-Thiothymine: Investigations By Electron Attachment And Electron Transmission Spectroscopies, Stanislav A. Pshenichnyuk, Gordon A. Gallup, Paul Burrow Jan 2007

Low-Energy Electron Capture By 6-Aza-2-Thiothymine: Investigations By Electron Attachment And Electron Transmission Spectroscopies, Stanislav A. Pshenichnyuk, Gordon A. Gallup, Paul Burrow

Paul Burrow Publications

The interaction of low-energy (0-10 eV) electrons with 6-aza-2-thiothymine is investigated in the gas phase by studies of sharp structure in the total electron scattering cross section and by mass analysis of the stable or long-lived negative ions produced by electron attachment. The most efficient fragmentation process, occurring at 0.15 eV, involves the ejection of a closed-shell neutral molecule (CH3CN). Ab initio calculations support our proposal that this process leads to ring closure to form a stable four-member heterocyclic anion. A long-lived parent anion with an approximate lifetime of 75 microseconds is observed near zero electron energy, and …


Anisotropic Magnetoresistance In Colossal Magnetoresistive La1−Xsrxmno3 Thin Films, Jeng-Bang Yau, X. Hong, A. Posadas, C. H. Ahn, W. Gao, E. Altman, Y. Bason, L. Klein, M. Sidorov, Z. Krivokapic Jan 2007

Anisotropic Magnetoresistance In Colossal Magnetoresistive La1−Xsrxmno3 Thin Films, Jeng-Bang Yau, X. Hong, A. Posadas, C. H. Ahn, W. Gao, E. Altman, Y. Bason, L. Klein, M. Sidorov, Z. Krivokapic

Xia Hong Publications

We report on magnetic field and temperature-dependent measurements of the anisotropic magnetoresistance (AMR) in epitaxial La1−xSrxMnO3 (LSMO) thin films. While in 3d ferromagnetic alloys increasing the magnetization, either by reducing the temperature or increasing the magnetic field, increases the AMR, we find that in LSMO films the AMR dependence on magnetization displays nonmonotonic behavior which becomes particularly pronounced in lightly doped compounds. We believe that this behavior is related to the inhomogeneity exhibited by these materials.


Planar Hall Effect In Epitaxial Thin Films Of Magnetite, Y. Bason, L. Klein, H. Q. Wang, J. Hoffman, X. Hong, V. E. Henrich, C. H. Ahn Jan 2007

Planar Hall Effect In Epitaxial Thin Films Of Magnetite, Y. Bason, L. Klein, H. Q. Wang, J. Hoffman, X. Hong, V. E. Henrich, C. H. Ahn

Xia Hong Publications

We measured the planar Hall effect (PHE) of magnetite (Fe3O4) films between 150 and 350 K. The PHE was measured both with a constant magnetic field rotating in the plane of the sample and in a remanent state after applying a field in specific directions. The PHE amplitude decreases with temperature; however, it changes little between 300 and 350 K. The remanent PHE signal is as high as 10 V/A, larger than previously observed in manganite films. We also measured the PHE in the remanent state and found that its magnitude and stability make it a …


A Relation Between Energies Of The Short-Lived Negative Ion States And Energies Of Unfilled Molecular Orbitals For A Series Of Bromoalkanes, S. A. Pshenichnyuk, N. L. Asfandiarov, Paul Burrow Jan 2007

A Relation Between Energies Of The Short-Lived Negative Ion States And Energies Of Unfilled Molecular Orbitals For A Series Of Bromoalkanes, S. A. Pshenichnyuk, N. L. Asfandiarov, Paul Burrow

Paul Burrow Publications

A series of bromoalkanes was investigated by means of electron transmission spectroscopy in the gas phase. Experimental values of vertical electron affinities associated with occupation of the LUMO by an incoming electron were assigned using ab initio quantum chemical calculations. The predicted vertical electron affinity values differ from measured ones by at most ±0.2 eV.


Magnetic Enhancement In Cobalt-Manganese Alloy Clusters, Shuangye Yin, Ramiro Moro, Xiaoshan Xu, Walter A. De Heer Jan 2007

Magnetic Enhancement In Cobalt-Manganese Alloy Clusters, Shuangye Yin, Ramiro Moro, Xiaoshan Xu, Walter A. De Heer

Xiaoshan Xu Papers

Magnetic moments of CoNMnM and CoNVM clusters (N ≤ 60; M ≤ N/3) are measured in molecular beams using the Stern-Gerlach deflection method. Surprisingly, the per atom average moments of CoNMnM clusters are found to increase with Mn concentration, in contrast to bulk CoMn. The enhancement with Mn doping is found to be independent of cluster size and composition in the size range studied. Meanwhile, CoNVM clusters show reduction of average moments with increasing V doping, consistent with what is expected in bulk CoV. The results are …