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Full-Text Articles in Physics

Stiefel And Grassmann Manifolds In Quantum Chemistry, Eduardo Chiumiento, Michael Melgaard Apr 2012

Stiefel And Grassmann Manifolds In Quantum Chemistry, Eduardo Chiumiento, Michael Melgaard

Articles

We establish geometric properties of Stiefel and Grassmann manifolds which arise in relation to Slatertype variational spaces in many-particle Hartree-Fock theory and beyond. In particular, we prove thatthey are analytic homogeneous spaces and submanifolds of the space of bounded operators on the single-particle Hilbert space. As a by-product we obtain that they are complete Finsler manifolds. These geometric properties underpin state-of-the-art results on existence of solutions to Hartree-Fock type equations.


Kinetic Studies Of The Photo-Degradation Of Poly Arylene Vinylenes, Luke O'Neill, Patrick Lynch, Niamh Mcgoldrick, Hugh Byrne, Mary Mcnamara Apr 2012

Kinetic Studies Of The Photo-Degradation Of Poly Arylene Vinylenes, Luke O'Neill, Patrick Lynch, Niamh Mcgoldrick, Hugh Byrne, Mary Mcnamara

Articles

The kinetics of the degradation of a homologous series of Poly phenylene vinylenes in which the phenylene units of the PPV structure are systematically substituted by naphthyl and anthyrl units is presented. Degradation is monitored according to the decay of the long wavelength absorption maximum upon illumination with UV radiation. Compared to Toluene solution, the photo-degradation is seen to be accelerated in Chloroform solution. All decays are fitted with first order kinetics. It is found that all substitutions improve the stability of the vinylene polymers against decay. In particular the highly electro-negative naphthyl group serves to drastically increase the stability …


Nonlinear Optical Properties Of Carbon Nanotube Hybrids In Polymer Dispersions, Jun Wang, Kang-Shyang Liao, Daniel Früchtl, Ying Tian, Aisling Gilchrist , T, Nigel Alley, Enrico Andreoli, Brad Aitchison, Albert Nasibulin, Hugh Byrne, Esko I. Kauppinen, Long Zhang, Werner Blau, Seamus Curran Jan 2012

Nonlinear Optical Properties Of Carbon Nanotube Hybrids In Polymer Dispersions, Jun Wang, Kang-Shyang Liao, Daniel Früchtl, Ying Tian, Aisling Gilchrist , T, Nigel Alley, Enrico Andreoli, Brad Aitchison, Albert Nasibulin, Hugh Byrne, Esko I. Kauppinen, Long Zhang, Werner Blau, Seamus Curran

Articles

A series of double-walled carbon nanotubes (DWNTs) and multi-walled nanotubes (MWNTs) functionalized with selected organic chromophores, fluorescein 5(6)-isothiocyanate (FITC), rhodamine B isothiocyanate (RITC) and fullerene (C60) were synthesized by covalently linking these electron-donor groups to the metallic nanotubes. These versatile carbon nanotube composites show remarkable nonlinear optical (NLO) performance, due to a merged effect of the complementary NLO characteristics of the moieties of the composites. The hybrids were characterized by UV-Vis spectroscopy and Raman spectroscopy. Evidence suggests charge transfer species are formed between the chromophores and the nanotubes. The optical limiting performance of the DWNT, MWNT hybrids and …