Browsing by Subject "Ground state"

Article

Analysis of the excited-state absorption spectral bandshape of oligofluorenes

Hayes, Sophia C.; Silva, C. (2010)

We present ultrafast transient absorption spectra of two oligofluorene derivatives in dilute solution. These spectra display a photoinduced absorption band with clear vibronic structure, which we analyze rigorously using ...

Article

Binding of ligands containing carbonyl and phenol groups to iron(iii): new Fe6, Fe10 and Fe12 coordination clusters

Kitos, Alexandros A.; Papatriantafyllopoulou, Constantina; Tasiopoulos, Anastasios J.; Perlepes, Spyros P.; Escuer, Albert; Nastopoulos, Vassilios (2017)

The initial use of ligands 2′-hydroxyacetophenone (HL1), 2-hydroxybenzophenone (HL2) and 2,2′-dihydroxybenzophenone (H2L3) in iron(iii) chemistry is described. The syntheses and crystal structures are reported for five ...

Article

Competing broken-symmetry and rotationally symmetric spin-singlet states in a few-electron quantum dot in a magnetic field

Avetisyan, A.; Moulopoulos, Konstantinos; Djotyan, Anahit P. (2008)

On the basis of developed variational many-body approach, within a second quantized formulation, the nature of the ground state of a few-electron system in a parabolic two-dimensional (2D) quantum dot (QD) is theoretically ...

Conference Object

Coulomb repulsive correlation in A3B5 semiconductor quantum dots in the presence of a magnetic field

Avetisyan, A. A.; Djotyan, Anahit P.; Moulopoulos, Konstantinos (2006)

The ground state total and correlation energies of a negative ion-electron and electron-electron systems in a parabolic QD with standard dispersion law are theoretically investigated in an external magnetic field by a ...

Article

Coulomb repulsive correlation in systems with radial confinement: Quantum dots and the Overhauser model in an external magnetic field

Avetisyan, A. A.; Moulopoulos, Konstantinos; Djotyan, Anahit P. (2006)

The ground-state correlation energy of an electron-negative ion system in a spherical quantum dot (QD) with parabolic confinement in an external homogeneous magnetic field is investigated. Both cases of finite and infinite ...

Article

Effect of halogen substitution on p-phenylenebiscarbene

Nicolaïdes, Andrew N. (2005)

The effect of halogen (F, Cl, and Br) perturbation on the geometries and relative energies of five electronic states (one quintet, two triplets, and two singlets) of p-phenylenebiscarbene (1-H) was examined computationally ...

Conference Object

Effect of molecular weight on the vibronic structure of a diketopyrrolopyrrole polymer

Hayes, Sophia C.; Pieridou, Galatia K.; Vezie, M.; Few, S.; Bronstein, H.; Meager, I.; McCulloch, I.; Nelson, J. (SPIE, 2016)

Resonance Raman Spectroscopy (RRS) is employed in this study to examine the influence of molecular weight on the optical response of a diketopyrrolopyrrole polymer (DPP-TT-T) in solution. The vibronic structure observed ...

Article

Evolution of a Bose-Einstein condensate in a rapidly expanding circular box

Theodorakis, Stavros; Constantinou, Y. (2007)

We examine the evolution of the ground state of a Bose-Einstein condensate in a two-dimensional circular box, the wall of which is initially at rest and then recedes with large and constant speed. The final state of the ...

Article

Exciton-donor complexes in semiconductor quantum dots in a magnetic field: Infinite and finite potential barriers

Avetisyan, A.; Djotyan, Anahit P.; Kazaryan, E.; Moulopoulos, Konstantinos (2008)

The binding energy of the ground state of a charged exciton-donor complex in a spherical semiconductor quantum dot with infinite and finite potential barriers as well as the oscillator strength for the optical transition ...

Article

A family of 3D coordination polymers composed of Mn19 magnetic units

Moushi, Eleni E.; Stamatatos, Theocharis C.; Wernsdorfer, W.; Nastopoulos, Vassilios; Christou, George; Tasiopoulos, Anastasios J. (2006)

(Figure Presented) Singles networks: The use of 1,3-propanediol and of 2-methyl-1,3-propanediol in manganese carboxylate chemistry leads to two new 3D coordination polymers with an unprecedented Mn19 repeating unit. The ...

Article

Femtosecond UV pump/near-IR probe studies of the solvent-dependent excited-state decay dynamics of chlorine dioxide

Hayes, Sophia C.; Cooksey, C. C.; Wallace, P. M.; Reid, P. J. (2001)

The excited-state decay and geminate-recombination dynamics of chlorine dioxide (OClO) are investigated using UV pump/near-IR probe spectroscopy. Experiments are performed with 200-fs time resolution on OClO dissolved in ...

Conference Object

Few-electron systems in a quantum dot in a magnetic field: The Wigner molecule and paired electron phases

Avetisyan, A. A.; Moulopoulos, Konstantinos (2006)

We have developed a variational many-body description for few-electron systems in a parabolic quantum dot in an external magnetic field. The ground state energy of the electronic system has been theoretically investigated ...

Article

Geometrically strained carbenes: Interdependence among geometry, spin multiplicity and reactivity

Takahashi, Y.; Nicolaïdes, Andrew N.; Tomioka, H. (2001)

The singlet and triplet states of cyclobutenylidene 1 and benzocyclobutenylidene 2 have been studied computationally (using ab initio and DFT methods) in order to assess the effect of angle strain on the S-T gap of vinyl- ...

Article

Inducing single-molecule magnetism in a family of loop-of-loops aggregates: Heterometallic Mn40Na4 clusters and the homometallic Mn44 analogue

Moushi, Eleni E.; Lampropoulos, Christos; Wernsdorfer, W.; Nastopoulos, Vassilios; Christou, George; Tasiopoulos, Anastasios J. (2010)

The syntheses, crystal structures, and magnetic properties of a new family of heterometallic Mn40Na4 and homometallic Mn44 loop-of-loops aggregates are reported. The reactions of [Mn3O(O 2CMe)6(py)3]•py with 1,3-propanediol ...

Article

Magnetic "Molecular Oligomers" Based on Decametallic Supertetrahedra: A Giant Mn49 Cuboctahedron and its Mn25Na4 Fragment

Manoli, Maria; Alexandrou, Sofia; Pham, L.; Lorusso, G.; Wernsdorfer, W.; Evangelisti, M.; Christou, George; Tasiopoulos, Anastasios J. (2016)

Two nanosized Mn49 and Mn25Na4 clusters based on analogues of the high-spin (S=22) [MnIII 6MnII 4(μ4-O)4]18+ supertetrahedral core are reported. Mn49 and Mn25Na4 complexes consist of eight and four decametallic supertetrahedral ...

Article

A microporous Co2+ metal organic framework with single-crystal to single-crystal transformation properties and high CO2 uptake

Moushi, Eleni E.; Kourtellaris, Andreas; Spanopoulos, Ioannis; Manos, Manolis J.; Papaefstathìou, Giannis S.; Trikalitis, Pantelis N.; Tasiopoulos, Anastasios J. (2015)

The synthesis and characterization of {[Co9(INA)18(H2O)6]·11DMF·15H2O}∞ (Co9-INA·11DMF·15H2O) (INA- = the anion of isonicotinic acid) is reported. It exhibits a rigid 3D-porous structure with a Co9 repeating unit consisting ...

Article

Non-peturbative density expansions for extended Coulomb systems

Moulopoulos, Konstantinos (2000)

We present a general non-perturbative argument that combines the Pauli and virial theorems for a multicomponent translationally invariant Coulombic system of fermions at zero temperature, and which by an iteration procedure ...

Article

Piecewise analytic approximation for Bose-Einstein condensates in isotropic harmonic traps

Theodorakis, Stavros (2004)

Analytic simulacra of the wave functions in the regions around the origin and far from the origin were constructed to emulate the ground state and the single-vortex state of a Bose-Einstein condensate in an isotropic ...

Article

Piecewise linear emulator of the nonlinear Schrödinger equation and the resulting analytic solutions for Bose-Einstein condensates

Theodorakis, Stavros (2003)

A most general method for finding very good analytic approximate solutions to the cubic nonlinear Schrodinger equation is presented. This method applies whenever the nonlinearity in that equation is a purely cubic one. It ...

Article

The production and decay kinetics of CIOO in water and freon-11: A time-resolved resonance Raman study

Hayes, Sophia C.; Thomsen, C. L.; Reid, P. J. (2001)

The production and decay kinetics of ClOO in water and freon-11 were studied using time-resolved resonance Raman (TRRR) spectroscopy. The formation of ClOO following OClO photoexcitation at 390 nm was investigated using ...