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91.
A. Perrin J. Demaison H. Bürger 《Journal of Quantitative Spectroscopy & Radiative Transfer》2012,113(11):1226-1232
The hot band 3ν9?ν9 of the isotopologue 11BF2OH (difluoroboric acid) located at 1034.78 cm?1 was investigated for the first time by Fourier transform infrared spectroscopy. During previous studies both, the ν9 mode (OH-torsion relative to the BF2 moiety, at 522.87 cm?1) and the ν4 mode (in-plane OH bend) had been shown to exert large amplitude motion, and splittings of 0.0051 and 0.0038 cm?1 had been observed in the interacting 2ν9 and ν4 bands located at 1042.87 and 961.49 cm?1, respectively. The present work establishes large amplitude effects also for the 93 excited state located at 1557.655 cm?1. Numerous P and R transitions of the 3ν9–ν9 hot band were identified in the 2ν9 manifold, and doublets corresponding to a torsional splitting of 0.031 cm?1 in the 93 state were observed. The vibrational assignment of the 93 state was confirmed by the detection of the 3ν9?2ν9 hot band Q branch in the 19 μm region. 相似文献
92.
93.
Pascal Dréan Denis Petitprez Jean Demaison Juan Carlos López José Luis Alonso Jean-Claude Guillemin James E. Boggs 《Journal of Molecular Spectroscopy》1998,190(2):365-371
The rotational spectrum of vinylarsine in the ground state has been studied in the range 7–320 GHz. The spectra of asynconformer and agaucheconformer have been unambiguously assigned on the basis of the existence of ab-type or ac-type spectrum. Rotational constants, quartic, and some sextic centrifugal distortion constants were derived. For thesynform, measurements of lowJaR0,1transitions in a pulsed-nozzle Fourier transform microwave spectrometer (FTMWS) enabled the determination of the diagonal elements of the quadrupole tensor, as well as two spin–rotation constants.Ab initiocalculations performed at the MP2 level using the 6-311++G(3df, 3pd) basis set reproduced experimental rotational constants within 0.2%. 相似文献
94.
G. Wlodarczak F. Herlemont J. Demaison A. Fayt J.G. Lahaye 《Journal of Molecular Spectroscopy》1985,112(2):401-412
The ν6 fundamental of CH335Cl has been remeasured by using a Stark-Lamb-dip technique. These Stark resonances were combined with the zero-field microwave spectra to give determinable combinations of the vibration-rotation parameters and the dipole moments: μ″ = 1.89628(23)D and μ′ = 1.89738(19)D. 相似文献
95.
The methyl-top moments of inertia and planar moments of inertia of a large number of compounds have been obtained from rotational spectroscopic data and are compared with the corresponding quantities obtained from ab initio geometries. Ab initio geometry refinements have been performed with the 4-21G basis set using standard gradient techniques. High correlation is found between the spectroscopic and calculated values, indicating the possibility of using experimental methyl-top moments of inertia as a source of structural information on methyl groups. 相似文献
96.
The equilibrium structure of cis-thionylimide, HNSO has been determined using high-level ab initio calculations and various experimental procedures. The Laurie correction to the N-H bond length is discussed and it is shown that it can be estimated by ab initio methods. The results are found to be in good agreement and the best equilibrium structure is (in Å for the bond lengths): r(N–H) = 1.020(1), r(N–S) = 1.510(2), r(S–O) = 1.448(1), (HNS) = 115.94(39)°, and (NSO) = 120.44(10)°. 相似文献
97.
The ground state rotational spectrum of propionitrile has been reinvestigated between 8 and 250 GHz. A total of 218 transitions with J ≤ 48 and K ≤ 21 have been assigned. These data have been analyzed in terms of a reduced Hamiltonian similar to, but different from that proposed by Watson. All the determinable constants up to the sextic terms have been significantly determined. The rotational constants are (in MHz): 相似文献
98.
99.
Guest-Prof. Dr. Jean Demaison Prof. Dr. Natalja Vogt Rizalina Tama Saragi Marcos Juanes Prof. Emeritus Dr. Heinz Dieter Rudolph Prof. Dr. Alberto Lesarri 《Chemphyschem》2019,20(3):366-373
The disulfide bridge (−S−S−) is an important structural motif in organic and protein chemistry, but only a few accurate equilibrium structures are documented. We report the results of supersonic-jet microwave spectroscopy experiments on the rotational spectra of diphenyl disulfide, C6H5−S−S−C6H5 (including all 13C and 34S monosubstituted isotopologues), and the determination of the equilibrium structure by the mixed estimation (ME) method. A single conformation of C2 symmetry was observed in the gas phase. This disulfide is a challenging target since its structure is determined by 34 independent parameters. Additionally, ab initio calculations revealed the presence of three low-frequency vibrations (<50 cm−1) associated to phenyl torsions which would prevent the calculation of an accurate force field. For this reason, instead of the semiexperimental method, we used the mass-dependent (rm) method to fit the structural parameters concurrently to moments of inertia and predicate parameters, affected with appropriate uncertainties. The predicates were obtained by high-level quantum-chemical computations. A careful analysis of the results of different fits and a comparison with the ab initio optimizations confirms the validity of the used methods, providing detailed structural information on the title compound and the disulfide bridge. 相似文献
100.
A PerrinJ.-M Flaud B BakriJ Demaison O BaskakovS.V Sirota M HermanJ.Vander Auwera 《Journal of Molecular Spectroscopy》2002,216(2):203-213
The high-resolution (0.002 cm−1) spectrum of the ν7 (OCO scissor mode) and ν9 (COH torsion mode) fundamental bands of trans-formic acid (HCOOH) at 15.8 μm was recorded by Fourier transform infrared spectroscopy. In addition, millimeter-wave transitions within the 71 and 91 vibrational states were measured in the spectral range 340-600 GHz. Using these new experimental data, an extensive analysis of the ν7 and ν9 bands was performed. The model we have used accounts for the strong A- and B-type Coriolis interactions which couple the 71 and 91 vibrational states and which were already pointed out in the literature [J. C. Deroche, J. Kauppinen and E. Kyrö, J. Mol. Spectrosc.78, 379-394 (1979); E. Willemot, J. Mol. Spectrosc.120, 246-275 (1986)]. The observed levels are fit to within the experimental accuracy leading to the determination of a precise set of band centers of ν7 and ν9 at 686.1656 cm−1 and 640.7251 cm−1, respectively, and rotational and Coriolis constants. 相似文献