排序方式: 共有74条查询结果,搜索用时 31 毫秒
21.
Gediminas Gaigalas Zenonas Rudzikas Oliver Scharf 《Central European Journal of Physics》2004,2(4):720-736
The general tensorial form of the hyperfine interaction operator in the formalism of second quantization is presented. Both
diagonal and off-diagnonal matrix elements of the above-mentioned operator are found using an approach based on a combination
of second quantization in the coupled tensorial form, angular momentum theory in three spaces (orbital, spin and quasispin)
and a generalised graphical technique. This methodology allows us to account for correlation effects efficiently and, therefore,
to study the hyperfine interactions in complex many-electron atoms, those with openf-shells included, in a practical manner. All this will lead us to design an efficient program for large scale calculations
of hyperfine structure and isotope shift. 相似文献
22.
23.
Algirdas Audzijonis Gediminas Gaigalas Leonardas Žigas Audrius Pauliukas Raimundas Žaltauskas Aurimas Čerškus Jurgis Narusis 《Central European Journal of Physics》2005,3(3):382-394
This paper presents the theoretical investigation of energy levels of valence bands (VB) and core levels (CL) of the ferroelectric
SbSl single crystals in antiferroelectric and ferroelectric phases. Since the best approximation for the deep VB levels is
a calculation by the Hartree-Fock method, the molecular model of a SbSI crystal was used for calculations. This model of the
crystal was also used for calculations of the total density of states. It was found that the VB and CL of this ferroelectric
semiconductor are sensitive to the small lattice distortion at the phase transition, and that an average of the total density
of states, when all atoms participate in oscillations of all normal modes, are more similar to the experimental X-ray photoelectron
spectra (XPS). The experimental splitting of CL obtained by XPS was compared with the theoretically calculated one by two
different methods. The cluster model calculations showed that the splitting of the CL in SbSI might be caused by photoelectron
emission from the atoms, which have different valence state, at the surface. 相似文献
24.
Guillo P Hamelin O Batat P Jonusauskas G McClenaghan ND Ménage S 《Inorganic chemistry》2012,51(4):2222-2230
In our research program aiming to develop new ruthenium-based polypyridine catalysts for oxidation we were interested in combining a photosensitizer and a catalytic fragment within the same complex to achieve catalytic light-driven oxidation. To respond to the lack of such conjugates, we report here a new catalytic system capable of using light to activate water molecules in order to perform selective sulfide oxygenation into sulfoxide via an oxygen atom transfer from H(2)O to the substrate with a TON of up to 197 ± 6. On the basis of electrochemical and photophysical studies, a proton-coupled electron-transfer process yielding to an oxidant Ru(IV)-oxo species was proposed. In particular, the synergistic effect between both partners in the dyad yielding a more efficient catalyst compared to the bimolecular system is highlighted. 相似文献
25.
Mažeikienė Regina Niaura Gediminas Malinauskas Albertas 《Journal of Solid State Electrochemistry》2019,23(6):1631-1640
Journal of Solid State Electrochemistry - A comparative Raman spectroelectrochemical study on polyaniline electrodeposited at a gold electrode was performed within the broad range of spectra... 相似文献
26.
Masato Takenaka Yoshikazu Hashimoto Takeshi Iwasa Tetsuya Taketsugu Gediminas Seniutinas Armandas Balčytis Saulius Juodkazis Yoshiaki Nishijima 《Journal of computational chemistry》2019,40(8):925-932
First principles electrodyanmics and quantum chemical simulations are performed to gain insights into the underlying mechanisms of the surface enhanced Raman spectra of 22BPY adsorbed on pure Au and Ag as well as on Au–Ag alloy nanodiscs. Experimental SERS spectra from Au and Ag nanodiscs show similar peaks, whereas those from Au–Ag alloy reveal new spectral features. The physical enhancement factors due to surface nano-texture were considered by numerical FDTD simulations of light intensity distribution for the nano-textured Au, Ag, and Au–Ag alloy and compared with experimental results. For the chemical insights of the enhancement, the DFT calculations with the dispersion interaction were performed using Au20, Ag20, and Au10Ag10 clusters of a pyramidal structure for SERS modeling. Binding of 22BPY to the clusters was simulated by considering possible arrangements of vertex and planar physical as well as chemical adsorption models. The DFT results indicate that 22BPY prefers a coplanar adsorption on a (111) face with trans-conformation having close energy difference to cis-conformation. Binding to pure Au cluster is stronger than to pure Ag or Au–Ag alloy clusters and adsorption onto the alloy surface can deform the surface. The computed Raman spectra are compared with experimental data and assignments for pure Au and Ag models are well matching, indicating the need of dispersion interaction to reproduce strong Raman signal at around 800 cm–1. This work provides insight into 3D character of SERS on nanorough surfaces due to different binding energies and bond length of nanoalloys. © 2018 Wiley Periodicals, Inc. 相似文献
27.
Evaldas Stankevičius Mantas Garliauskas Mindaugas Gedvilas Nikolai Tarasenko Gediminas Račiukaitis 《Annalen der Physik》2017,529(12)
Here, the structuring of surfaces with gold nanoparticles by using Bessel‐like beam array is demonstrated. The experimental results show that the fabricated microring structures containing gold nanoparticles have a surface plasmon resonance in the spectral range of 520–540 nm, which can be tuned by selecting the laser treatment parameters. Fabricated microring structures exhibit a lower light transmittance comparing with the randomly distributed gold nanoparticles for wavelengths 500–570 nm due to the growth in the size of nanoparticles. In the spectral range of 600–700 nm, the light transmittance through microring structures is higher compared with the randomly distributed gold nanoparticles because of the removal of gold nanoparticles as gold has high reflectivity for wavelengths longer than 600 nm. The demonstrated method enables an easy fabrication of microring structures having tunable plasmonic properties. 相似文献
28.
Electronic Energy Transfer Modulation in a Dynamic Foldaxane: Proof‐of‐Principle of a Lifetime‐Based Conformation Probe 下载免费PDF全文
Dr. Sergey A. Denisov Quan Gan Xiang Wang Dr. Luca Scarpantonio Dr. Yann Ferrand Dr. Brice Kauffmann Dr. Gediminas Jonusauskas Dr. Ivan Huc Dr. Nathan D. McClenaghan 《Angewandte Chemie (International ed. in English)》2016,55(4):1328-1333
Abiotic aromatic oligoamide foldamers are shown to self‐assemble in solution to form a double helix, which can accommodate a bichromophoric thread in its central void. While in solution reversible electronic energy transfer is instilled between chromophoric termini of the free, flexible thread as evidenced through delayed luminescence, upon rigidification of the rod the chromophores are mutually distanced and effectively decoupled. Consequently, the chromophores display their individual photophysical characteristics. The observed conformation‐dependent changes of dynamic luminescence properties, which are particularly sensitive to distance, offers a new strategy for lifetime‐based detection of geometry on the molecular scale as demonstrated through real‐time luminescence detection of molecular complexation leading to foldaxane formation. 相似文献
29.
Petruleviciene Milda Parvin Maliha Savickaja Irena Gece Gintare Naujokaitis Arnas Pakstas Vidas Pilipavicius Jurgis Gegeckas Audrius Gaigalas Gediminas Juodkazyte Jurga 《Journal of Solid State Electrochemistry》2022,26(4):1021-1035
Journal of Solid State Electrochemistry - Light-assisted electrochemical processes have the potential to replace energy-intensive electrosynthesis technologies, especially in the area of strong... 相似文献
30.
Stephanie Delbaere Elena V. Tulyakova Emilie Marmois Gediminas Jonusauskas Elena N. Gulakova Yuri V. Fedorov Olga A. Fedorova 《Tetrahedron》2013
We report here about effective FRET process (73–99%) in mono-Mg2+ complexes of symmetrical crown ether bis(styryl) dyes. The FRET process has not been observed in the free state and in binuclear complexes. The formation of mononuclear complex provides two styrylic fragments with appropriate positions of absorption and emission bands for FRET. The other important parameter for FRET is the proper geometric orientation of both chromophores, which attain sandwich conformation with close positioning of complexed and free styryl fragments induced by ion-modulated geometry reorganization of the bis-dye. 相似文献