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1
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Angular Differential Cross-Section for Electron Transfer in ION-ION Collision

100%
Bhattacharyya S., Bhattacharyya S., Mitra S.
Acta Physica Polonica A
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1998
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vol. 93
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issue 4
601-610
EN
Angular differential cross-sections for the formation of He^{0} in collision between fast He^{+} ions are calculated using distorted wave Coulomb-Born approximation. The interaction potentials satisfy necessary Coulomb boundary conditions. In absence of any other theoretical results the present results are compared with the existing experimental data.
2
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The Scattering of Positrons and Positronium by Atoms in the Close-Coupling Approximation

63%
Hewitt R. N., Noble C. J., Bransdfen B. H.
Acta Physica Polonica A
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1995
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vol. 88
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issue 1
139-145
EN
We present some recent results obtained within the close-coupling approximation for both positron and positronium scattering by atoms. We begin by discussing a generalization of the method of Vincent and Phatak to study the formation of Ps- in Ps collisions with H(1s) in a simplified model. The important result of this calculation is that the overall Coulomb interaction which is present in the rearrangement channel is treated exactly. We also present results for positronium formation and ionization for positron scattering by argon atoms. The present calculations are for transitions from the Αr(3s^{2}) subshell and show the importance of the coupling to the continuum.
3
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Angular Differential Cross-Sections for Electron Transfer in Collisions between Proton and He^{+}(1s) Ions

63%
Bhattacharyya S., Pathak K., Becker A., Faisal F.
Acta Physica Polonica A
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1996
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vol. 90
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issue 6
1143-1153
EN
Angular differential cross-sections for the formation of H, as a result of electron capture by proton from He^{+}(1s) at the centre-of-mass energies from 4 to 24 keV, are calculated using distorted wave Coulomb-Born approximation. The total interaction potentials in the prior-interaction channel and in the post-interaction channel are considered. Coulomb boundary conditions are taken care of with the proper choice of the perturbation potentials in both the prior and the post channels. A prior-post discrepancy is noted. Existing theoretical results are presented along with the present results.
4
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Fluorescence Properties of An Electron Acceptor Substituted Bis-Pyrazolo-Pyridine Derivative: NO_{2}-DMPP

63%
Rechthaler K., Schamschule R., Parusel A., Rotkiewicz K., Piorun D., Köhler G.
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vol. 95
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issue 3
321-334
EN
The fluorescence properties of 3,5-dimethyl-1,7-diphenyl-4 -(4'-nitro-phenyl)-bis-pyrazolo-[3,4-b;4',3'-e]-pyridine (NO_{2}-DMPP) and its parent compound 3,5-dimethyl-1,7-diphenyl-bis-pyrazolo-[3,4-b;4',3'-e]-pyridine (BPP, without the nitrophenyl substituent) were investigated. BPP is a highly fluorescent blue emitter and the fluorescence properties, the emission wavelength, and the fluorescence quantum yield, depend only slightly on solvent. On the contrary, acceptor substituted NO_{2}-DMPP shows dual fluorescence: A long-wavelength component experiences a red-shift with increasing solvent polarity but is efficiently quenched when the polarity exceeds that of solvents like 1,2-dichloroethane or 1-bromopropane. A weak short-wavelength component changes only slightly its position and intensity upon variation of the solvent but its yield increases strongly at low temperatures. The experimental results are discussed in the context of the results of semiempirical calculations which show that fluorescence originates from two closely lying fluorescent states which change their sequence and properties when the polarity of the solvent is varied. A twisted intramolecular charge transfer (TICT) state does most likely not contribute to the emission properties, because of its high energy.
5
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Selective Resonance Raman Scattering of Peierls-Hubbard (TTF^{+})_{2} Dimers in (TTF)_{2}Mo_{6}O_{19} and (TTF)_{2}W_{6}O_{19} Salts

63%
Kruszewski S., Feltre L., Bozio R., Bellitto C.
|
EN
Raman investigation of Peierls-Hubbard (TTF^{+})_{2} dimers in (TTF)_{2}Mo_{6}O_{19} and (TTF)_{2}W_{6}O_{19} salts have been performed. It was found that the resonance enhancement of Raman intensity of intramolecular vibration modes exists only when the frequency of excitation light fits to the localised electron transition, however, the resonance enhancement of intermolecular modes occurs when the frequency of excitation light corresponds to the charge transfer transition.
6
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Antihydrogen Formation in Low Energy Collision of Positron with Antiproton

51%
Bhattacharyya S.
Acta Physica Polonica A
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1994
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vol. 86
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issue 3
297-308
EN
In the present paper two-body radiative recombination rate for the production of antihydrogen (H̅) in a merged beam of slow positrons (e^{+}) and antiprotons (p¯) is studied in the light of a two-step process, which consists of capture in an excited state of H̅ with subsequent decay to the ground state and emission of a photon. Computation is done using the field theory and the Coulomb gauge. Importance of the two-step radiative recombination process relative to the well-known spontaneous photorecombination process, on the two-body radiative recombination rate for antihydrogen formation, is discussed. The present result predicts higher contribution from the two-step radiative recombination process as compared to the spontaneous photorecombination process to the rate of cold antihydrogen formation with the relative collision energy below 0.01 Rydberg, near which experiments are being conducted. However, above 0.1 Rydberg the spontaneous photorecombination process dominates over the two-step radiative recombination process. The present result is valid, as well, for the formation of hydrogen atom due to collision between slow electron and proton.
7
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Content available

Effect of an Adsorbed Atom on Resonant Charge Exchange in Atom Scattering on Metal Surfaces

51%
Taranko R., Taranko E., Wiertel M.
Acta Physica Polonica A
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2003
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vol. 103
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issue 5
483-497
EN
A simple model describing resonant charge transfer between the free-electron metal surface and an atom colliding with it at some distance from another adsorbed atom is presented. The negative ionization probability of a scattered atom is studied within the time-dependent Anderson-Newns model and the time-evolution operator approach. With appropriate models for the considered system, the ionization probability is shown to oscillate with the distance between the adsorbed atom and the collision point of the scattered atom with the metal surface. These oscillations are results of the indirect interaction between the adsorbed and the scattered atoms due to the coupling of both atoms with the metal energy band.
8
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Excited States of Intermolecular Electron-Donor-Acceptor Systems and Internal Geometry of Complex' Components

51%
Deperasińska I., Sobieraj A.
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vol. 95
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issue 3
309-319
EN
In this work we present the results of semiempirical AM1 calculations of the energy of electron-donor-acceptor system in the ground and excited states with full optimization of the complex geometry (in terms of both: intermolecular and intramolecular coordinates). A comparison of these results with those obtained for separated acceptor and donor molecules enables the estimation of the energetic effects of changes in internal structure of donor and acceptor which accompany the process of formation and stabilization of excited charge-transfer state. It is shown that energies corresponding to those changes are comparable with the energy of intermolecular interactions between donor and acceptor molecules.
9
Content available remote

Influence of Protein Vibrations on Electron Transfer

51%
Babincová M., Babinec P.
Acta Physica Polonica A
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1993
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vol. 84
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issue 2
365-367
EN
Using a double well model complemented with the third excited state it is shown that a new excited-state-induced protein vibration-mediated channel, with an electron transfer rate comparable to a standard tunneling rate may exist. This channel can become dominant at low temperatures.
10
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Content available

Resonant Charge Exchange in Atom Scattering on Atoms Adsorbed on Metal Surfaces

51%
Wiertel M., Taranko E., Taranko R.
Acta Physica Polonica A
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2002
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vol. 101
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issue 6
837-855
EN
The ionization probability of an atom scattered from an atom adsorbed on a metal surface has been studied theoretically within the time-dependent Anderson-Newns model. The effect of the metal electron density of states, the band filling as well as the relative position of the scattered atom and adsorbed atom energy levels have been considered and the comparison with the results obtained for clean surfaces has been made.
11
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Theoretical Analysis of the Electronic Ground and Excited Franck-Condon State of 2-Alkylamino-(3, 5, or 6)-Methyl-4-Nitropyridine N-oxides

51%
Deperasińska I., Makarewicz A., Szemik-Hojniak A.
Acta Physica Polonica A
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2007
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vol. 112
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issue S
S-71-S-84
EN
We theoretically characterised properties of the electronic ground and excited Franck-Condon state of 2-alkylamino-(3, 5, or 6)-methyl-4- -nitropyridine N-oxides. The obtained results of time-dependent density functional theory calculations are consistent with the experimental absorption spectra. The nature of the lowest excited states of the considered N-oxides molecules is discussed. Two excited singlet states (in the midst of four lowest states) have the charge-transfer character. These states have different charge-transfer contribution of the two electron donor groups to the same electron acceptor. In consequence, different conditions for the promotion of intramolecular proton transfer in excited state are created in each case.
12
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Multi-mode ground state interaction terms in C60-based electron donor-acceptor complexes

26%
Sheka E.
Open Physics
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2004
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vol. 2
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issue 2
300-328
EN
Quantum-chemical testing of donor-acceptor properties of binary molecular complexes, related to the singlet state, is suggested as QCh calculations of studied systems and their constituents by using both spin-nondependent (RHF) and spindependent (UHF) versions of the exploited computational tool. The avoided crossing of intermolecular interaction terms of neutral moleculesE int(A 0 B 0) and molecular ionsE int(A + B −) causes a multi-mode character of the ground state term. The dependence of D-A complex properties on the type of the term, space positions of the term minimum, and the interrelation of the corresponding energies are discussed. The suggested approach has been applied to binary complexes C60+X (X=TAE, TDAE, DMMA, COANP, 2Li, Mg).
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