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951.
952.
Time-dependent density functional theory calculations have been performed for the excited states of psoralen, 5-methoxypsoralen, and 8-methoxypsoralen in systems and furan and pyrone monoadducts bonded to a thymine residue. The theoretical assignments to ultraviolet (UV) absorption spectra of isolated systems have been performed. The present calculations have clarified that the excitation energies of the first singlet excited (S1) state of monoadducts are blue-shifted compared with the isolated systems. It is shown that, in particular, the S1 excitation energy of the pyrone monoadduct is significantly blue-shifted and, therefore, the pyrone monoadduct is not excited by UV-A light (300-400 nm), which is used in the photochemotherapy. 相似文献
953.
954.
Hirata KS Inoue K Ishida T Kajita T Kihara K Nakahata M Nakamura K Ohara S Sato N Suzuki Y Totsuka Y Yaginuma Y Mori M Oyama Y Suzuki A Takahashi K Yamada M Koshiba M Nishijima K Suda T Tajima T Miyano K Miyata H Takei H Fukuda Y Kodera E Nagashima Y Takita M Kaneyuki K Tanimori T Beier EW Feldscher LR Frank ED Frati W Kim SB Mann AK Newcomer FM Van Berg R Zhang W 《Physical review D: Particles and fields》1991,44(8):2241-2260
955.
956.
957.
We have used a low energy variational RVB wave function to evaluate the kinetic energy of holons in the dilute limit. We report results on a 5×5 cluster; from the first 8 moments of the density of states, we estimate a lower band edge for the holon, which is fairly insensitive to details of the RVB wave function. This band edge is higher than the corresponding one for a hole in the Néel state, by about 0.08t, in the limitU/t. 相似文献
958.
N. Gunasekara T. Takahashi F. Maeda T. Sagawa H. Suematsu 《Zeitschrift für Physik B Condensed Matter》1988,70(3):349-355
The electronic band structure of the first stage alkali-metal graphite intercalation compounds (C8K, C8Rb and C8Cs) was determined by angle-resolved ultraviolet photoelectron spectroscopy. The dispersive feature of the * bands at
point in the Brillouin zone was clearly observed in all the compounds. The electron occupancies in the * band of C8K, C8Rb and C8Cs were estimated to be 0.5±0.05 e (e; unit electronic charge), 0.45±0.05 e and 0.4±0.05 e, respectively. This strongly suggests that another half of the unit electronic charge is accommodated in the three-dimensional band at point, which forms a spherical Fermi surface at the center of the Brillouin zone. The character of the three-dimensional band at point was also discussed.He died on 27th of September, 1986 相似文献
959.
960.
C. D. Bredl K. Petersen S. Arnold G. Sparn F. Steglich S. Takahashi M. Tachiki B. Runtsch T. Wolf 《Zeitschrift für Physik B Condensed Matter》1992,86(2):187-191
We report measurements of the low-temperature thermal conductivity of YBa2Cu3O7– (0.1) single crystals (T
c
=84 K) both parallel (
a, b
) and perpendicular (
c
) to the CuO2 planes. Whereas
c
(T) is found to be identical, within experimental resolution, with the phonon contribution
ph
(T),
a, b
(T) contains an additional term linear in temperature,AT. We ascribeAT to the contribution of unpaired electronic carriers residing in the chain layers. Measurements performed in external magnetic fieldsB8 T support this interpretation. Our observations can be explained by an internal multilayer (IML) model in which it is assumed that strong superconductivity is generated within the CuO2 layers and weak superconductivity is induced in the chain layers by the proximity effect. The fit of the experimental results to the IML model reveals that approximately 15% of the electronic carriers remain unpaired in YBa2Cu3O7 belowT=1 K. 相似文献