共查询到20条相似文献,搜索用时 0 毫秒
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Z. Janas L. Batist J. Döring M. Gierlik R. Kirchner J. Kurcewicz H. Mahmud C. Mazzocchi A. Płochocki E. Roeckl K. Schmidt P. J. Woods J. Żylicz 《The European Physical Journal A - Hadrons and Nuclei》2005,23(3):401-408
The very neutron-deficient 117Ba nuclei were produced in 58Ni-induced reactions on a 63Cu target and selected for spectroscopic studies by using BaF+ molecules formed in the ion source of the GSI on-line mass separator. The -decay of 117Ba was investigated by means of the total absorption -ray spectrometer and a telescope for -delayed particle detection. In the analysis combining the -delayed -ray and proton data the energy window available for -delayed proton emission, the branching ratios for proton transitions to the 116Xe levels and the -feeding of the -ray and proton-emitting 117Cs states were determined. The -strength function for 117Ba derived from the measured -feeding distribution revealed the existence of a broad resonance structure at 117Cs excitation energy of about 4-5 MeV. The results of the -delayed proton studies and -strength measurements are confronted with theoretical predictions. 相似文献
3.
We have used a stringy model of quantum space–time foam to suggest that the vacuum may exhibit a non-trivial refractive index depending linearly on γ -ray energy: η−1∼Eγ/MQG1, where MQG is some mass scale typical of quantum gravity that may be ∼1018 GeV: see [J. Ellis, N.E. Mavromatos, D.V. Nanopoulos, Phys. Lett. B 665 (2008) 412] and references therein. The MAGIC, HESS and Fermi γ-ray telescopes have recently probed the possible existence of such an energy-dependent vacuum refractive index. All find indications of time-lags for higher-energy photons, but cannot exclude the possibility that they are due to intrinsic delays at the sources. However, the MAGIC and HESS observations of time-lags in emissions from AGNs Mkn 501 and PKS 2155-304 are compatible with each other and a refractive index depending linearly on the γ -ray energy, with MQG1∼1018 GeV. We combine their results to estimate the time-lag Δt to be expected for the highest-energy photon from GRB 080916c measured by the Fermi telescope, which has an energy ∼13.2 GeV, assuming the redshift z=4.35±0.15 measured by GROND. In the case of a refractive index depending linearly on the γ -ray energy we predict Δt=26±11 s. This is compatible with the time-lag Δt?16.5 s reported by the Fermi Collaboration, whereas the time-lag would be negligible in the case of a refractive index depending quadratically on the γ-ray energy. We suggest a strategy for future observations that could distinguish between a quantum-gravitational effect and other interpretations of the time-lags observed by the MAGIC, HESS and Fermi γ-ray telescopes. 相似文献
4.
Roman Tomaschitz 《Physics letters. A》2008,372(24):4344-4349
Tachyonic spectral densities of ultra-relativistic electron populations are fitted to the γ-ray spectra of two TeV blazars, the BL Lacertae objects 1ES 0229+200 and 1ES 0347-121. The spectral maps are compared to Galactic TeV sources, the γ-ray binary LS 5039 and the supernova remnant W28. In contrast to TeV photons, the extragalactic tachyon flux is not attenuated by interaction with the cosmic background light; there is no absorption of tachyonic γ-rays via pair creation, as tachyons do not interact with infrared background photons. The curvature of the observed γ-ray spectra is intrinsic, caused by the Boltzmann factor of the electron densities, and reproduced by a tachyonic cascade fit. In particular, the curvature in the spectral map of the Galactic microquasar is more pronounced than of the two extragalactic γ-ray sources. Estimates of the thermodynamic parameters of the thermal or, in the case of supernova remnant W28, shock-heated nonthermal electron plasma generating the tachyon flux are obtained from the spectral fits. 相似文献
5.
D. Montanari S. Leoni D. Mengoni G. Benzoni N. Blasi G. Bocchi P.F. Bortignon A. Bracco F. Camera G. Colò A. Corsi F.C.L. Crespi B. Million R. Nicolini O. Wieland J.J. Valiente-Dobon L. Corradi G. de Angelis F. Della Vedova E. Fioretto A. Gadea D.R. Napoli R. Orlandi F. Recchia E. Sahin R. Silvestri A.M. Stefanini R.P. Singh S. Szilner D. Bazzacco E. Farnea R. Menegazzo A. Gottardo S.M. Lenzi S. Lunardi G. Montagnoli F. Scarlassara C. Ur G. Lo Bianco A. Zucchiatti M. Kmiecik A. Maj W. Meczynski A. Dewald Th. Pissulla G. Pollarolo 《Physics letters. [Part B]》2011
6.
Christopher D. Thompson Ivana Aleksic Don McNaughton 《Journal of Molecular Spectroscopy》2005,230(2):133-138
The FTIR spectrum of pentafluoroethane (R125) was measured in the mid infrared region from 900 to 4000 cm−1. Vibrational assignments for R125 are revised by comparison of previous and current experimental data with ab initio calculations at both the MP2/6-311+(d,p) and B3LYP/TZV+(3df,3p) levels of theory. High resolution FTIR spectra were recorded at room temperature and in an enclosive flow cell at a rotational temperature of 140 K. The cold spectrum was sufficiently resolved to enable rovibrational analyses of the overlapping ν4 (1200.7341 cm−1) and ν13 (1223.3 cm−1) bands, which have a/c hybrid and b-type character, respectively. Ground state combination differences were used to confirm assignment of 2375 lines to ν4 (Jmax = 86, Ka max = 50) and 2921 lines to ν13 (Jmax = 60, Ka max = 54). Effective rotational and centrifugal distortion constants were determined for ν4, and the polarization ratio was found to be . Severe Coriolis perturbations prevent any satisfactory fit to the ν13 band. 相似文献
7.
Martian regolith and Earth’s basaltoid samples have been investigated by means of Mössbauer spectroscopy. The identification of the same minerals: olivine, pyroxene, magnetite, hematite and confrontation of the Fe3?+?/Fe2?+?, Fe3?+?/Fetot, Fe2?+?/Fetot ratios are presented. Co-existence of olivine and hematite in Martian regolith, absent in presented by authors terrestrial samples has been tentatively explained. 相似文献
8.
The absorption spectrum of the ν2 fundamental band of the cis-conformer of the transient molecule HOPO, namely the terminal PO stretching mode, has been detected and measured using diode laser spectroscopy. The molecule was generated in a discharge flow system containing hydrogen and white phosphorus vapour (P4) and a trace of oxygen. The spectrum has the appearance of an a-type band of a near prolate asymmetric top. Above Ka = 5 the spectrum is perturbed and transitions terminating on these higher Ka levels were excluded from the fit. The vibrational frequency and rotational constants derived from the unperturbed parts of the spectrum are compatible with new high precision ab initio calculations reported here. A combined fit of the ν2 band and the ν4 band data, measured earlier, was carried out. The ν2 band origin was determined to be 1258.539525(32) cm−1, approximately 5.5 cm−1 higher than the matrix value. 相似文献
9.
The ν2 (CD3 symmetrical deformation) and ν5 (CD3 degenerate deformation) fundamental bands of CD3Br were studied by 9.4- and 10.4-μm CO2 laser Stark spectroscopy. Stark resonances originating from 28 and 53 rovibrational transitions of the ν2 and ν5 bands, respectively, were assigned for each of the isotopic species, CD379Br and CD381Br. These two bands were simultaneously analyzed with explicit inclusion of the ν2-ν5 Coriolis interaction, yielding precise molecular constants in the ν2 and ν5 excited states as well as the Coriolis coupling constant. The molecular constants obtained are consistent between the two isotopic species and are in good agreement with the results of high-resolution infrared studies. The band origins and dipole moments are
CD379Br | CD381Br | |||||
991.396 82 (18) | 991.388 46 (17) | cm?1 | ||||
1055.469 00 (12) | 1055.466 32 (12) | cm?1 | ||||
1.830 42 (52) | 1.829 84 (47) | D | ||||
1.829 93 (48) | 1.829 57 (46) | D | ||||
1.832 23 (60) | 1.831 19 (56) | D |
4391.3230(84) | 0.582(154) | 2.4830(32) | ||||
4391.1921(94) | 0.594(179) | 2.4073(37) |
35ClO2 | 37ClO2 | |||||
945.592 357(60) | 939.602 909(66) | cm?1 | ||||
μ′ | 1.788 39(13) | 1.788 46(15) | D | |||
μ″ | 1.791 95(10) | 1.792 10(13) | D | |||
δμ | ?0.003 56(18) | ?0.003 64(26) | D |
Ground | ||
μ (D) | 1.653 511 (29) | 1.658 514 (23) |
α (Å3) | ?0.77 (32) | ?0.58 (48) |
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