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Two-Photon Resonance Fluorescence, Moorad Alexanian, Subir K. Bose
Two-Photon Resonance Fluorescence, Moorad Alexanian, Subir K. Bose
Faculty Bibliography 2000s
We present a theory of two-photon resonance fluorescence of an atom or molecule in which the excitation by an external electromagnetic field as well as fluorescence emission is mediated by two-photon processes. The treatment is based on first dressing the atom or molecule by the external field and then evaluating perturbatively the effect of the interaction with the vacuum or fluorescent field and so resonance fluorescence can be considered as spontaneous emission from the dressed atom. The introduction of the combined system of atom and external field via dressed states leads to simpler calculations and more transparent physics. The fluorescence …
Solvent Effects On The Three-Photon Absorption Cross-Section Of A Highly Conjugated Fluorene Derivative, Ion Cohanoschi, Kevin D. Belfield, Carlos Toro, Florencio E. Hernández
Solvent Effects On The Three-Photon Absorption Cross-Section Of A Highly Conjugated Fluorene Derivative, Ion Cohanoschi, Kevin D. Belfield, Carlos Toro, Florencio E. Hernández
Faculty Bibliography 2000s
Herein, we report the study of the three-photon absorption cross-section dependence on solvents parameters for a highly conjugated organic dye, 2,2(')-(4,4(')-(1E,1(')E)-2,2(')-(9,9-didecyl-9H-fluorene-2,7-diyl) bis(ethene-2,1-diyl)bis(4,1-phenylene))dibenzo[d]thiazole (A-pi-pi-pi-A). The three-photon absorption cross-section was measured for this organic dye in solution in four different solvents with polarity function, Delta f between 0.162 and 0.247. The experiments show how the solvent's reorientation of the electrons and polarity contribute to the 3PA cross-section. Multiphoton-absorption experiments of A-pi-pi-pi-A in all four different solvents were performed with a tunable OPG pumped by a 25 picosecond Nd-YAG laser.
The Impact Of The Pi-Electron Conjugation Length On The Three-Photon Absorption Cross Section Of Fluorene Derivatives, Ion Cohanoschi, Kevin D. Belfield, Carlos Toro, Sheng Yao, Florencio E. Hernández
The Impact Of The Pi-Electron Conjugation Length On The Three-Photon Absorption Cross Section Of Fluorene Derivatives, Ion Cohanoschi, Kevin D. Belfield, Carlos Toro, Sheng Yao, Florencio E. Hernández
Faculty Bibliography 2000s
The three-photon absorption cross sections of three different fluorene derivatives, with extended pi-electron conjugation lengths was experimentally measured and compared with shorter pi-electron conjugation length analogs. The effect of the conjugation length on the three-photon absorption cross section sigma(3)' of this family of molecules has been elucidated. It is demonstrated that sigma(3)' of the asymmetric compound D-pi-pi-pi-A is 6.6 times larger than its shorter configuration D-pi-A, while for the symmetric compounds D-pi-pi-pi-D and A-pi-pi-pi-A a two-fold enhancement was found relative to their shorter conjugation length analogs. Measurements of the three-photon excitation of these compounds in THF solution (10(-3)M) were accomplished …
Calculation Of Loosely Bound Levels For Three-Body Quantum Systems Using Hyperspherical Coordinates With A Mapping Procedure, Viatcheslav Kokoouline, Françoise Masnou-Seeuws
Calculation Of Loosely Bound Levels For Three-Body Quantum Systems Using Hyperspherical Coordinates With A Mapping Procedure, Viatcheslav Kokoouline, Françoise Masnou-Seeuws
Faculty Bibliography 2000s
In view of modelization of experiments involving cold atoms and molecules, we develop a method that allows us to calculate weakly bound levels of triatomic molecules. The method combines (1) the hyperspherical coordinates to describe interparticle motion in the three-body system, (2) the solution of the Schrodinger equation in two steps: determination of adiabatic states for a fixed hyper-radius and then solution of a set of coupled hyper-radial equations using the slow variable representation of Tolstikhin [J. Phys. B: At. Mol. Opt. Phys. 29, L389 (1996)], (3) and a mapping procedure that reduces considerably the number of basis functions needed …
Density Functional Theory Study Of Water Adsorption At Reduced And Stoichiometric Ceria (111) Surfaces, Santosh Kumar, Patrick K. Schelling
Density Functional Theory Study Of Water Adsorption At Reduced And Stoichiometric Ceria (111) Surfaces, Santosh Kumar, Patrick K. Schelling
Faculty Bibliography 2000s
We study the structure and energetics of water molecules adsorbed at ceria (111) surfaces for 0.5 and 1.0 ML coverages using density functional theory. The results of this study provide a theoretical framework for interpreting recent experimental results on the redox properties of water at ceria (111) surfaces. In particular, we have computed the structure and energetics of various absorption geometries at the stoichiometric ceria (111) surface. We find that single hydrogen bonds between the water and the oxide surface are favored in all cases. At stoichiometric surfaces, the water adsorption energy depends rather weakly on coverage. We predict that …
Renner-Teller Effects In Hco+ Dissociative Recombination, Ivan A. Mikhailov, Viatcheslav Kokoouline, Åsa Larson, Stefano Tonzani, Chris H. Greene
Renner-Teller Effects In Hco+ Dissociative Recombination, Ivan A. Mikhailov, Viatcheslav Kokoouline, Åsa Larson, Stefano Tonzani, Chris H. Greene
Faculty Bibliography 2000s
A theoretical description of the dissociative recombination process for the HCO+ ion suggests that the nonadiabatic Renner-Teller coupling between electronic and vibrational degrees of freedom plays an important role. This finding is consistent with a recent study of this process for another closed-shell molecule, the H-3(+) ion, where Jahn-Teller coupling was shown to generate a relatively high rate. The cross section obtained here for the dissociative recombination of HCO+ exhibits encouraging agreement with a merged-beam experiment.