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Wyświetlanie 1-11 z 11
Tytuł:
Emission of Acridine and its Aggregates Isolated in the Neon Matrix
Autorzy:
Prochorow, J.
Kozankiewicz, B.
Dongo Gemi, Bango Bango
Morawski, O.
Powiązania:
https://bibliotekanauki.pl/articles/1992729.pdf
Data publikacji:
1998-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.50.+w
33.50.-j
Opis:
The results of experimental studies of fluorescence and phosphorescence of acridine in the low-temperature inert neon matrix, at 7 K, are reported. It is found that the low-temperature inert matrix of neon affects the energy levels of acridine molecules very weakly even as compared with nonpolar (aprotic) and non-reactive solvent (e.g. hexane) and that there are different sites for acridine molecules in the neon matrix. However, the observed fluorescence spectra are strongly dependent on the excitation wavelength and besides the different (monomer) sites other emitting species are also contributing to the observed fluorescence emission of acridine in the neon matrix. Clear-cut evidence of the formation of singlet excimers of acridine in the neon matrix demonstrates itself as a very broad and structureless fluorescence spectrum with a relatively large shift from the origin of monomer (site) fluorescence which is characterized by a very distinct vibrational structure. The phosphorescence emission was observed only for the monomers. The observed differences in the low-energy part of excitation spectra of phosphorescence and fluorescence are discussed in terms of the close-lying excited singlet states of n,π* and π,π* character (mixed by the vibronic coupling) and tentatively interpreted as due to the formation of resonance acridine dimers. Their fluorescence spectrum is slightly shifted toward lower energies from the origin of monomer (site) fluorescence.
Źródło:
Acta Physica Polonica A; 1998, 94, 5-6; 749-760
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrafast Energy Relaxation and Excitation Delocalization in Excited States of Zinc Porphyrin Dimers and Trimer
Autorzy:
Yamazaki, I.
Akimoto, S.
Yamazaki, T.
Shiratori, H.
Osuka, A.
Powiązania:
https://bibliotekanauki.pl/articles/1994082.pdf
Data publikacji:
1999-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.50.+w
78.47.+p
Opis:
Ultrafast excited-state relaxation process has been studied with zinc porphyrin dimers and circular trimer. Following 80 fs excitation at Soret band (420 nm) or Q band (580 nm) of zinc porphyrin, the fluorescence decay curves exhibit ultrafast decays with lifetimes of 80 fs in o-dimer, 450 fs in trimer and 540 fs in m-dimer. The timeresolved fluorescence spectra show that the fast decay process correspond to disappearance of monomer-like emission followed by red-shifted and broaden spectra. These ultrafast processes are assigned as due to excitation transfer among monomers and delocalization of excitation yielding excitonic states.
Źródło:
Acta Physica Polonica A; 1999, 95, 1; 105-120
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Picosecond Transient Absorption of Xanthene Dyes
Autorzy:
Berndt, O.
Bandt, F.
Eichwurzel, I.
Stiel, H.
Powiązania:
https://bibliotekanauki.pl/articles/1994630.pdf
Data publikacji:
1999-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.50.+w
33.50.-j
78.47.+p
Opis:
After one- and two-colour ps-excitation the transient absorption of rose bengal, erythrosin B and eosin Y in the spectral range from 450 to 670 nm was probed using picosecond continuum pulses generated in H$\text{}_{2}$O-D$\text{}_{2}$O mixture. Our experiments showed for all dyes a high T$\text{}_{1}$-T$\text{}_{n}$ absorption signal above 590 nm where no ground state absorption occurs. These excited triplet states can be effectively populated by a delayed second pump pulse. Their properties with special attention to reverse intersystem crossing processes from T$\text{}_{n}$ to S$\text{}_{x}$ are discussed.
Źródło:
Acta Physica Polonica A; 1999, 95, 2; 207-220
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Luminescent Probe for Highly Energetic Collisions in Mixtures of Complex Molecules with Acceptors of Vibrational and Triplet Energy
Autorzy:
Zalesskaya, G. A.
Yakovlev, D. L.
Sambor, E. G.
Baranovsky, D. I.
Powiązania:
https://bibliotekanauki.pl/articles/2008324.pdf
Data publikacji:
1999-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.50.+w
34.50.Ez
34.90.+q
Opis:
Pressure dependences of intensities and decay rates of time-resolved luminescence of acetophenone, benzophenone, anthraquinone were used to obtain the efficiencies of vibrational and triplet-triplet energy transfer. It was shown that vibrational relaxation of the chosen molecules can be interpreted in terms of two consecutive processes: rapid collisional relaxation of molecules from initially prepared states to a vibrational distribution at T$\text{}_{vib}$ by vibration-vibration process and relaxation of this vibrational distribution to the thermal one (vibration-translation process). At relatively small internal energy < 10000 cm$\text{}^{-1}$, the collisional efficiencies of the vibration-vibration process in mixtures with polyatomic bath gases had values typical of processes with a supercollision contribution. Molecules relaxed from the upper vibrational level to the vibrational distribution after several collisions (2-3). The average energies transferred per collision are well correlated with predictions of the simple ergodic theory of collisional energy transfer. The majority of the collisions took part only in vibration-translation energy transfer of relatively small energies. The efficiencies of triplet-triplet energy transfer were analyzed for acetophenone, benzophenone and anthraquinone as donors and biacetyl-acceptor in a gas phase when energy of about 20000 cm$\text{}^{-1}$ was transferred. It permitted us to elucidate the common features of highly energetic collisions. It was shown that the efficiencies are much lower than the gas kinetic ones and depended on the vibrational energy and temperature. It was discussed how to enhance triplet-triplet efficiencies due to vibrational excitation of a donor molecule.
Źródło:
Acta Physica Polonica A; 1999, 95, 6; 897-910
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectroscopy of 2-aminopurine: An MCSCF Study
Autorzy:
Rachofsky, E. L.
Ross, J. B. A.
Krauss, M.
Osman, R.
Powiązania:
https://bibliotekanauki.pl/articles/1992724.pdf
Data publikacji:
1998-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.15.Ar
31.50.+w
33.20.Lg
33.50.Dq
Opis:
2-aminopurine is a highly fluorescent isomer of adenine that can be incorporated into DNA as a probe of structure, dynamics, and protein-DNA interactions. Interpretation of the fluorescence of 2-aminopurine in DNA requires a model of the electronic structure of this fluorophore in its ground and excited states. To this end, electronic structures and energies of the ground and lowest singlet excited states of 2-amino-9-methylpurine were calculated by the multiconfiguration self-consistent field method supplemented by multiconfiguration perturbation theory. The molecular geometry was optimized in both of these electronic states to permit investigation of both electronic excitation and fluorescence emission. The predicted energies and transition dipoles were in good agreement with experiment. The permanent molecular dipole of 2-amino-9-methylpurine increased upon excitation, suggesting that both the absorption and emission spectra should shift to slightly lower energies in polar solvents. The anomalous spectral shifts observed in water suggest that 2-aminopurine undergoes hydrogen bonding that better stabilizes the ground state than the excited state. From the calculated electrostatic potentials of these two states, the position at which this hydrogen bond forms was predicted. These results form a basis for understanding the excited states and possible intermolecular interactions of 2-aminopurine in DNA.
Źródło:
Acta Physica Polonica A; 1998, 94, 5-6; 735-748
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Excited States in Solid Phenothiazine as Studied by Electroabsorption Spectroscopy
Autorzy:
Kalinowski, J.
Stampor, W.
Fattori, V.
Di Marco, P.
Powiązania:
https://bibliotekanauki.pl/articles/1933431.pdf
Data publikacji:
1995-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.50.+w
31.70.Dk
31.70.Ks
33.55.Be
Opis:
Electric field modulated absorption spectra of vapor deposited layers of phenothiazine, explained in terms of a quadratic Stark effect, indicate modification of intramolecular (Frenkel-type) excitons by charge transfer transitions throughout UVIS absorption spectrum in the range 250-450 nm. The charge transfer character of the excited states appears at energies characteristic of various oxidation products of phenothiazine as identified from a spectroscopic study of photochemical air oxidation, performed on solution and solid film samples of this compound. The charge transfer transitions are ascribed to electron transfer between the molecules of phenothiazine and their oxidized species created in the samples during preparation and handling procedures.
Źródło:
Acta Physica Polonica A; 1995, 87, 6; 953-964
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoinduced Electron Transfer in Jet Cooled Molecular Complexes
Autorzy:
Piuzzi, F.
Uridat, D.
Dimicoli, I.
Mons, M.
Tramer, A.
LeBarbu, K.
Lahmani, F.
Zehnacker-Rentien, A.
Powiązania:
https://bibliotekanauki.pl/articles/1994237.pdf
Data publikacji:
1999-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.50.+w
32.30.-r
33.15.-e
33.20.-t
Opis:
Exciplex and excimer formation have been probed in several jet cooled complexes using mass selective two-photon ionisation and fluorescence excitation spectroscopy as well as ground state depletion spectroscopy (hole burning): (i) In the anthracene-dimethyl-ortho-toluidine system, it has been found that the ionisation step takes place with a much higher efficiency from the charge transfer state responsible for the exciplex emission than from the locally excited state giving rise to the resonant fluorescence. (ii) The dimer, trimer, and higher clusters of anthracene all show only excimer emission. When compared to the dimer, the trimer exhibits a peculiar behaviour (structured fluorescence excitation and hole burning spectra, short lifetime and low ionisation efficiency) which has been related to a significant locally excited character of the initially prepared state of the species excited state. (iii) The influence of an intermolecular hydrogen bond on the electron transfer process has been studied in the 2,2,2-trifluoro-1-(9-anthryl)ethanol- dimethylaniline system. A threshold for exciplex formation higher than in the case of the anthracene-dimethylaniline complex is observed.
Źródło:
Acta Physica Polonica A; 1999, 95, 1; 121-135
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DFT Estimation of Exchange Coupling Constant of Cr₈ Molecular Ring using the Hybrid Functional B3LYP
Autorzy:
Wojciechowski, M.
Brzostowski, B.
Kamieniarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1386209.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
71.15.Mb
73.22.-f
75.30.Et
31.15.E-
71.10.-w
Opis:
A study of electronic and magnetic properties of an octametallic chromium-based homonuclear molecule Cr₈F₈(CO₂-C(CH₃)₃)₁₆ is presented, using density functional theory (DFT) approach and linearized augmented plane wave (LAPW) method with Perdew, Burke and Ernzerhof (PBE) and Becke 3-term correlation (B3LYP) functionals. The exchange coupling parameters between transition metals ions are extracted, taking into account two different (ferro- and antiferromagnetic) spin configurations. The value J=3.1 meV found for the hybrid B3LYP functional improves significantly the one obtained for the PBE functional and gives an evidence for the superiority of the former in simulation of molecular nanomgnets. Moreover, the hybrid functional yields excellent spin density localisation, an enhancement of the HOMO-LUMO gaps and the value 2.81 $μ_B$ of magnetic moment at the chromium centre in good agreement with experiment.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 407-409
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mapping of the DFT Spin Configuration Energies of Cr8Cd Molecular Ring onto the Energy Structure of Falicov-Kimball Model
Autorzy:
Wojciechowski, M.
Brzostowski, B.
Lemański, R.
Kamieniarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1386266.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
71.15.Mb
73.22.-f
75.30.Et
31.15.E-
71.10.-w
Opis:
A comprehensive study of electronic and magnetic properties of a recently synthesized nonametalic chromium-based heteronuclear molecule Cr₈CdF₉(O₂C-C(CH₃)₃)₁₈ is presented, using DFT and Falicov-Kimball (FK) model approach. The magnetic moments are calculated and the spin charge density map is discussed. The exchange coupling parameters between transition metals ions are extracted, taking into account all the nonequivalent spin configurations. It is demonstrated that the energies of the spin configurations can be reproduced by the FK model with a set of parameters consistent with that for the parent Cr8 molecule. For molecular ring considered, the ground state corresponds to the antiferromagnetic configuration and the ferromagnetic configuration yields the highest energy.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 410-412
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Escape of O⁺ and CO⁺ Ions from Mars and Titan Atmospheres by Coulomb Explosion of CO₂²⁺ Molecular Dications
Autorzy:
Falcinelli, S.
Powiązania:
https://bibliotekanauki.pl/articles/1033346.pdf
Data publikacji:
2017-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.15.ag
31.50.Bc
33.15.Ta
33.80.Eh
37.20.+j
95.30.Cq
95.30.Dr
95.30.Ft
95.30.Ky
94.05.Rx
94.20.Cf
94.20.D-
94.20.dv
94.20.W-
94.20.wg
Opis:
Main properties of multiply charged molecular ions (energetics, structure, stability, lifetime and fragmentation dynamics) are relevant to know and to model the behavior of gaseous plasmas, planetary ionospheres, and astrophysical environments. Experimental measurements of the kinetic energy released of fragment ions produced by the Coulomb explosion of molecular dications (doubly charged molecular species) originating by double photoionization of CO₂ molecules, are reported and discussed. The kinetic energy released, as a function of the UV photon energy in the range of 34-50 eV, is extracted from the electron-ion-ion coincidence spectra recorded by using tunable synchrotron radiation coupled with ion imaging techniques at the GasPhase beam line of ELETTRA Synchrotron Light Laboratory Trieste, Italy. This kind of experiment allows assessing the probability of escape for simple ionic species in the ionosphere of Mars and Titan. The kinetic energy released, measured in the case of O⁺ and CO⁺ fragment ions, are ranging between 1.0-5.0 and 0.4-3.0 eV, respectively. These values are large enough to allow such ionic species in participating in the atmospheric escape from Mars (only O⁺ ions) and Titan (both O⁺ and CO⁺ ions) into space. In the case of Mars, we suggest a possible rationalization for the observed behavior of the O⁺ and CO₂²⁺ ion density profiles by Viking 1 lander and Mariner 6 spacecraft.
Źródło:
Acta Physica Polonica A; 2017, 131, 1; 112-116
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Warszawska rzeźba pomnikowa
Autorzy:
Grzesiuk-Olszewska, Irena (1937?-2021).
Współwytwórcy:
Bartoszewicz, Dariusz. Recenzja
Data publikacji:
2003
Wydawca:
Warszawa : Neriton
Tematy:
Królewskie Siły Powietrzne (RAF). Sto Czterdziesty Ósmy (148) Dywizjon Bombowy RAF 1944 r.
Pomnik Najmłodszym Żołnierzom Powstania Warszawskiego 1944 (2.10. 1999; Warszawa)
Pomnik Polskiego Państwa Podziemnego i Armii Krajowej (10.06. 1999; Warszawa)
Pomnik ku Czci Żołnierzy 1. Batalionu Szturmowego "Nałęcz" Armii Krajowej (31.07.1998; Warszawa)
Pomnik RAF-u (Royal Air Forces) (1997; Warszawa)
Pomnik "Pamięci Walczących o Wolność i Nieepodległość Rzeczypospolitej w 50. Rocznicę Sierpnia 1944 r." (1994; Warszawa)
Kotwica Polski Walczącej (8.10.1994; Warszawa)
Pomnik Błogosławionego Księdza Józefa Stanka SAC (23.09.1994; Warszawa)
Pomnik "Na Pamiątkę Walk Powstaniowych 1944 r. o Królikarnię i Szkołę na ul. Woronicza. Pułk AK "Baszta" (1994; Warszawa)
Pomnik Bohaterów Powstania Warszawskiego (1.08.1989; Warszawa)
Pomnik "Mokotów Walczący 1944" (27.04.1985; Warszawa)
Pomnik Żołnierzy "Baszty" (27.09.1984; Warszawa)
Pomnik Małego Powstańca (11.10.1983; Warszawa)
Pomnik Powstańców Warszawy (upamiętniający walki batalionu "Kiliński") (1.08.1979; Warszawa)
Pomnik Ofiar Czołgu-Pułapki (1975; Warszawa)
Pomnik Sapera, zwany również: "Chwała Saperom" (8.05.1975; Warszawa)
Pomnik "Polegli--Niepokonani 1939-1945" (20.09.1973; Warszawa)
Pomnik Żołnierzy AK Poległych w Ataku na Dworzec Gdański, zwany Nad Partyzancką Mogiłą (29.09.1957; Warszawa)
Pomnik Bohaterów Warszawy (Warszawa)
Opis:
S. 114, Pomnik Powstańców Czerniakowa i Żołnierzy 1. Armii Wojska Polskiego (31.07.1957; Warszawa).
S. 115, Pomnik Żołnierzy AK Poległych w Ataku na Dworzec Gdański, zwany Nad Partyzancką Mogiłą (29.09.1957; Warszawa).
S. 120-124, Pomnik Bohaterów Warszawy, zwany również "Warszawską Nike" lub "Nike" (20.07.1964; Warszawa).
S. 129-133, Pomnik "Polegli--Niepokonani 1939-1945" (20.09.1973; Warszawa).
S. 133-134, Pomnik Sapera, zwany również: "Chwała Saperom" (8.05. 1975; Warszawa).
S. 134-135, Pomnik Ofiar Czołgu-Pułapki (1975; Warszawa).
S. 141-142, Pomnik Powstańców Warszawy (upamiętniający walki batalionu "Kiliński") (1.08.1979; Warszawa).
S. 152, Pomnik Małego Powstańca (1.10.1983; Warszawa).
S. 153-154, Pomnik Żołnierzy "Baszty" (27.09.1984; Warszawa).
S. 157-158, Pomnik "Mokotów Walczący 1944" (27.04.1985; Warszawa).
S. 168-173, Pomnik Bohaterów Powstania Warszawskiego (1.08.1989; Warszawa).
S. 181, Pomnik "Na Pamiątkę Walk Powstaniowych 1944 r. o Królikarnię i Szkołę na ul. Woronicza. Pułk AK "Baszta" (1994; Warszawa).
S. 184-185, Pomnik Błogosławionego Księdza Józefa Stanka SAC (23.09. 1994; Warszawa).
S. 185-187, Kotwica Polski Walczącej (8.10.1994; Warszawa).
S. 188, Pomnik "Pamięci Walczących o Wolność i Niepodległość Rzeczypospolitej w 50. Rocznicę Sierpnia 1944 r." (1994; Warszawa).
S. 199-200, Pomnik RAF-u (Royal Air Forces) (1997; Warszawa).
S. 200-201, Pomnik ku Czci Żołnierzy 1. Batalionu Szturmowego "Nałęcz" Armii Krajowej (31.07.1998; Warszawa).
S. 208-213, Pomnik Polskiego Państwa Podziemnego i Armii Krajowej (10.06.1999; Warszawa).
S. 213-214, Pomnik Najmłodszym Żołnierzom Powstania Warszawskiego 1944 2.10.1999; Warszawa).
Rec.: Zdobią i straszą / Dariusz Bartoszewicz.
Dostawca treści:
Bibliografia CBW
Książka
    Wyświetlanie 1-11 z 11

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