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| 2. |
- Su, Bu-Mei, et al.
(författare)
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Sub-milliarcsecond radio structure of three quasars
- 2001
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Ingår i: Chinese Astronomy and Astrophysics. - : Elsevier. - 0275-1062 .- 1879-128X. ; 25:1, s. 23-28
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Tidskriftsartikel (refereegranskat)abstract
- The quasars, 0420-014, 0748+126 and 2251+158 (3C 454.3), have been observed at 1.3 cm with a global VLBI network. We have obtained the hybrid maps of the quasars at sub-milliarcsecond resolution. The brightness distribution is revealed in their nuclear regions. The observed data are fitted with a small number of Gaussian components. 2251+158 shows a core-jet structure, and its nuclear region is elongated in the direction PA= -130o. The jet is curved. Its observations at the epoch 1992.9 show it to be in the course of a large burst, accompanied by several smaller ones. The strongest component has a flux of ~ 4.11 Jy (67% of the total detected flux), mostly from an area of 0.16 x 0.01 mas. Doppler boosting is probably responsible for raising the brightness temperature up to 2.6 x 1012 K.
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| 3. |
- Wang, C. K., et al.
(författare)
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Solvent effects on the electronic structure of a newly synthesized two-photon polymerization initiator
- 2003
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 119:2, s. 1208-1213
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Tidskriftsartikel (refereegranskat)abstract
- Time-dependent hybrid density functional theory in combination with polarized continuum model has been applied to study the solvent effects on the geometrical and electronic structures, as well as one- and two-photon absorption processes, of a newly synthesized asymmetrical charge-transfer (CT) two-photon absorption (TPA) organic molecule. The TPA cross section calculated from a generalized two-state model and solvatochromic shift of the CT state are found to be solvent dependent, for which a nonmonotonic behavior with respect to the polarity of the solvents has been observed. The calculated properties are in good agreement with the experimental data available. The character of the CT state is visualized by plotting its charge density difference from ground state, in which an excess of electron density on the donor side of the molecule is found. This implies that the excited molecule is ready to donate its electron to the surroundings. The energetic aspect of the electron donation is discussed by examining the solvent dependence of the molecular ground state oxidation potential. The importance of the electron correlation for describing the two-photon absorption is also demonstrated.
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| 4. |
- Wang, Chuankui, et al.
(författare)
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Solvent dependence of solvatochromic shifts and the first hyperpolarizability of para-nitroaniline : a nonmonotonic behaviour
- 2003
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 119:8, s. 4409-
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Tidskriftsartikel (refereegranskat)abstract
- Solvent dependence of the electronic structure and nonlinear optical properties of the para-nitroaniline (pNA) molecule on the polarity of the solutions has been studied using the polarizable continuum model in combination with the hybrid density functional theory. With a supermolecular approach, specific hydrogen bonding effects have also been fully considered. Good agreement between theory and experiments are obtained for both solvatochromic shifts of the charge transfer state and the solvent-induced first hyperpolarizability of pNA.
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