47 research outputs found
Collectivity of plasmonic excitations in small sodium clusters with ring and linear structures
The collectivity of the electronic motion in finite systems is studied by using both the linear response density functional theory (LRDFT) and the collectivity index defined by the transition density matrix. We demonstrate a collectivity analysis on the size-dependent peaks of electronic excitations of small sodium clusters (rings and linear chains). We find the excitation-mode dependence of the collectivity and large collectivities for the higher-energy plasmonic excitations. The collectivity analysis also clarifies the existence of the nondipolar collective motion at the energies very close to the higher-energy plasmonic excitations. The importance of the nondipolar motion is pointed out in light of nano-optics
Significant Role of DNA Backbone in Mediating the Transition Origin of Electronic Excitations of B-DNA - Implication from Long Range Corrected TDDFT and Quantified NTO Analysis
We systematically investigate the possible complex transition origin of
electronic excitations of giant molecular systems by using the recently
proposed QNTO analysis [J.-H. Li, J.-D. Chai, G. Y. Guo and M. Hayashi, Chem.
Phys. Lett., 2011, 514, 362.] combined with long-range corrected TDDFT
calculations. Thymine (Thy) related excitations of biomolecule B-DNA are then
studied as examples, where the model systems have been constructed extracting
from the perfect or a X-ray crystal (PDB code 3BSE) B-DNA structure with at
least one Thy included. In the first part, we consider the systems composed of
a core molecular segment (e.g. Thy, di-Thy) and a surrounding physical/chemical
environment of interest (e.g. backbone, adjacent stacking nucleobases) and
examine how the excitation properties of the core vary in response to the
environment. We find that the orbitals contributed from DNA backbone and
surrounding nucleobases often participate in a transition of Thy-related
excitations affecting their composition, absorption energy, and oscillator
strength. In the second part, we take into account geometrically induced
variation of the excitation properties of various B-DNA segments, e.g. di-Thy,
dTpdT etc., obtained from different sources (ideal and 3BSE). It is found that
the transition origin of several Thy-related excitations of these segments is
sensitive to slight conformational variations, suggesting that DNA with thermal
motions in cells may from time to time exhibit very different photo-induced
physical and/or chemical processes.Comment: Main Text+Supplemental Materia
The Quantified NTO Analysis for the Electronic Excitations of Molecular Many-Body Systems
We show that the origin of electronic transitions of molecular many-body
systems can be revealed by a quantified natural transition orbitals (QNTO)
analysis and the electronic excitations of the total system can be mapped onto
a standard orbitals set of a reference system. We further illustrate QNTO on
molecular systems by studying the origin of electronic transitions of DNA
moiety, thymine and thymidine. This QNTO analysis also allows us to assess the
performance of various functionals used in time-dependent density functional
response theory.Comment: Main Text+Supplemental Material; G09 reference correcte
Discovery of a Giant Lyα Emitter Near the Reionization Epoch
‘In these times, during the rise in the popularity of institutional repositories, the Society does not forbid authors from depositing their work in such repositories. However, the AAS regards the deposit of scholarly work in such repositories to be a decision of the individual scholar, as long as the individual's actions respect the diligence of the journals and their reviewers.’ Original article can be found at : http://iopscience.iop.org/ Copyright American Astronomical SocietyWe report the discovery of a giant Lyα emitter (LAE) with a Spitzer/Infrared Array Camera (IRAC) counterpart near the reionization epoch at z = 6.595. The giant LAE is found from the extensive 1 deg2 Subaru narrowband survey for z = 6.6 LAEs in the Subaru/XMM-Newton Deep Survey (SXDS) field, and subsequently identified by deep spectroscopy of Keck/DEIMOS and Magellan/IMACS. Among our 207 LAE candidates, this LAE is not only the brightest narrowband object with L(Lyα) = 3.9 ± 0.2 × 1043 erg s–1 in our survey volume of 106 Mpc3, but also a spatially extended Lyα nebula with the largest isophotal area whose major axis is at least 3''. This object is more likely to be a large Lyα nebula with a size of 17 kpc than to be a strongly lensed galaxy by a foreground object. Our Keck spectrum with medium-high spectral and spatial resolutions suggests that the velocity width is v FWHM = 251 ± 21 km s–1, and that the line-center velocity changes by 60 km s–1 in a 10 kpc range. The stellar mass and star formation rate are estimated to be 0.9-5.0 × 1010 M and >34 M yr–1, respectively, from the combination of deep optical to infrared images of Subaru, UKIDSS-Ultra Deep Survey, and Spitzer/IRAC. Although the nature of this object is not yet clearly understood, this could be an important object for studying cooling clouds accreting onto a massive halo, or forming-massive galaxies with significant outflows contributing to cosmic reionization and metal enrichment of intergalactic medium.Peer reviewe
The 2006 November outburst of EG Aquarii: the SU UMa nature revealed
We report time-resolved CCD photometry of the cataclysmic variable EG Aquarii
during the 2006 November outburst During the outburst, superhumps were
unambiguously detected with a mean period of 0.078828(6) days, firstly
classifying the object as an SU UMa-type dwarf nova. It also turned out that
the outburst contained a precursor. At the end of the precursor, immature
profiles of humps were observed. By a phase analysis of these humps, we
interpreted the features as superhumps. This is the second example that the
superhumps were shown during a precursor. Near the maximum stage of the
outburst, we discovered an abrupt shift of the superhump period by
0.002 days. After the supermaximum, the superhump period decreased at the rate
of =, which is typical for SU UMa-type dwarf
novae. Although the outburst light curve was characteristic of SU UMa-type
dwarf novae, long-term monitoring of the variable shows no outbursts over the
past decade. We note on the basic properties of long period and inactive SU
UMa-type dwarf novae.Comment: 9 pages, 7 figures, accepted for PAS
Current Performance and On-Going Improvements of the 8.2 m Subaru Telescope
An overview of the current status of the 8.2 m Subaru Telescope constructed
and operated at Mauna Kea, Hawaii, by the National Astronomical Observatory of
Japan is presented. The basic design concept and the verified performance of
the telescope system are described. Also given are the status of the instrument
package offered to the astronomical community, the status of operation, and
some of the future plans. The status of the telescope reported in a number of
SPIE papers as of the summer of 2002 are incorporated with some updates
included as of 2004 February. However, readers are encouraged to check the most
updated status of the telescope through the home page,
http://subarutelescope.org/index.html, and/or the direct contact with the
observatory staff.Comment: 18 pages (17 pages in published version), 29 figures (GIF format),
This is the version before the galley proo