共查询到20条相似文献,搜索用时 31 毫秒
1.
We update our Standard Model predictions for g-2 of the muon and for the hadronic contributions (5) 2 to the running of the QED coupling, Δαbad^5)(MZ^2). Particular emphasis is put on recent changes in the hadronic contributions from new data in the 2π channel and from the energy region just below 2 GeV. 相似文献
2.
B3LYP level density functional theory (DFT) and multiconfiguration self-consistent-field (MCSCF) level ab initio method calculations have been performed on the basis of relativistic effective core potentials to investigate the nature of EuC and EuC2 molecules. The computed results indicate that the ground states of EuC and EuC2 are ^12∑^+ and SA2, respectively. Dissociation potential energy curves of the low-lying electronic states of EuC have been calculated using the MCSCF method, and the same level calculation on EuC2 indicates that the dissociation energy of EuC2 of ground state compares well with the available experimental data. The bond characteristic is also discussed using Mulliken populations. 相似文献
3.
《Journal of Molecular Spectroscopy》1987,124(2):437-442
Infrared measurements have been made on SO2 between 450 and 602 cm−1 with a resolution of 0.005 cm−1. The B-type bands due to the bending mode transitions 010-000 and 020-010 have been assigned and analyzed for the 32S16O2 molecule. A total of 3007 transitions were measured and fit for 32S16O2 with a standard deviation of 0.0004 cm−1. Ro-vibrational constants are given that fit the current measurements and the pure rotational transitions reported in the literature. 相似文献
4.
Artur M. S. Silva Hilário R. Tavares Ana I. N. R. A. Barros José A. S. Cavaleiro 《光谱学快报》2013,46(8):1655-1667
New 2′-hydroxychalcone and flavone derivatives have been synthesised. Their [1H] and [13C] NMR spectra were assigned by the application of COSY and HETCOR experiments and allowed the discussion of some structural aspects. It was shown on the basis of NOE experiments some configurational and conformational features of both type of compounds. 相似文献
5.
6.
《中国物理快报》2002,19(9):1280-1282
7.
We update our Standard Model predictions for g-2 of the muon and for the hadronic contributions to the running of the QED coupling,αh(5a)d(MZ2).Particular emphasis is put on recent changes in the hadronic contributions from new data in the 2π channel and from the energy region just below 2 GeV. 相似文献
8.
G. Di Lonardo L. Fusina A. Baldan R. Z. Martínez D. Bermejo 《Molecular physics》2013,111(21):2533-2542
Infrared and Raman spectra of dideuterated acetylene containing one 13C atom, 13C12CD2, have been recorded and analysed to obtain detailed information on the fundamental ν 2 band and associated combination and hot bands. Infrared spectra were recorded at 4?×?10?3?cm?1 resolution in the region 1150?2900?cm?1, which contains combination and hot bands from the ground and the bending v 4?=?1 and v 5?=?1 states. The Q-branches of the ν 2 fundamental and associated hot bands (ν 2?+?ν 4???ν 4, ν 2?+?ν 5???ν 5, ν 2?+?2ν 4???2ν 4, ν 2?+?2ν 5???2ν 5 and ν 2?+?ν 4?+?ν 5???(ν 4?+?ν 5)) were recorded using inverse Raman spectroscopy, with an instrumental resolution of about 3?×?10?3?cm?1. In addition, the observation of the 2ν 2???ν 2 Raman band was carried out populating the v 2?=?1 state by stimulated Raman pumping. In total, 11 Raman and 9 infrared bands were analysed, involving all the l-vibrational components of the excited stretching?bending manifolds up to v t ?=?v 4?+?v 5?=?2. A simultaneous analysis of all infrared and Raman assigned transitions has been performed on the basis of a theoretical model which takes into account the rotation and vibration l-type resonances within each vibrational manifold and the Darling?Dennison anharmonic resonance between the ν 2?+?2ν 4 and ν 2?+?2ν 5 states. The parameters obtained reproduce the assigned transition wavenumbers with a standard deviation of the same order of magnitude as the experimental uncertainty. 相似文献
9.
Oleinikov A. D. Mebel A. M. Azyazov V. N. 《Bulletin of the Lebedev Physics Institute》2020,47(3):97-100
Bulletin of the Lebedev Physics Institute - Abstract—Quantum-mechanical ab initio calculations are applied to study the growth mechanism of polycyclic aromatic hydrocarbons via reactions of... 相似文献
10.
We present an improved radiative pumping model for interstellar H2O and OH masers.This oversomes the defects of former radiative models,and is compatible with astronomical conditions.For the regions of strong H2O and OH formation,it is shown that the rotational population is affected by collisions less than by radiation.A reasonable scheme for both regeneration and destruction of interstellar H2O and OH molecules is investigated.It can close the dynamical cycle of interstellar H2O and OH species,and can give an appropriate interpretation for both interstellar H2O and OH masers.This model has been confirmed by experiments. 相似文献
11.
Rajesh Kharab Pardeep Singh Ravinder Kumar 《中国物理快报》2007,24(3):656-659
We investigate the effects of higher order multipole transitions, in particular electric quadrupole (E2) and El-E2 interference, on the Coulomb dissociation of 19 C within the framework of the first order eikonal approximation. The sensitivity of the total Coulomb breakup cross section and the longitudinal momentum distribution of the core fragment to these effects are checked. The breakup occurs predominately through the dipole transition and the contribution of E2 transition to the total cross section is found to be within the range from 1 to 3% of that of El. It is further observed that the El-E2 interference term contributes nothing to the integrated cross section. On the other hand, the longitudinal momentum distribution is observed to be insensitive to the E2 transition while the El-E2 interference introduces a small asymmetry in its shape. 相似文献
12.
GUO Yun-dong CAI Da-feng ZHOU Li-ping CHEN Xiang - rong YANG Xiang-dong 《原子与分子物理学报》2006,23(B04):241-245
For the superconductor MgB2, we have calculated the phonon density of states (DOS), phonon dispersion and Eliashberg function throughout the Brillouin zone (BZ), using an empirical potential model. The calculated values are consistent with the theoretical and experimental values. The calculated results show our empiricalpotential model is available for MgB2. 相似文献
13.
First-principles calculations of structural and thermodynamic properties of BeB2 compound 总被引:1,自引:0,他引:1 下载免费PDF全文
The lattice parameter bulk modulus and pressure derivative of BeB2 are calculated by using the Cambridge Serial Total Energy Package (CASTEP) program in the frame of density function theory. The calculated results agree well with the average experimental data and other theoretical results. Through the quasi-harmonic Debye model, the dependences of the normalized lattice parameters a/ao, c/c0 and the normalized primitive cell volume V/Vo on pressure P, the variation of the thermal expansion coefficient ~ with pressure P and temperature T, as well as the dependences of the heat capacity Cv on pressure P and temperature T are obtained systematically. 相似文献
14.
H. Hogreve 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,8(1):85-91
Electronic states of the molecular lithium anion are investigated by configuration-interaction calculations. Comparison with
the analogously computed potential energy curves for the lowest singlet and triplet states of the neutral Li2 shows that in addition to the well-known stable ground state X there also exist metastable excited states of Li
2
-
. Within the quartet sector, two candidates for such long-lived states are identified and their spectroscopic properties studied.
Received 23 March 1999 相似文献
15.
16.
We employ a first-principles plane wave method with the
relativistic analytic pseudopotential of Hartwigsen, Goedecker and Hutter
(HGH) scheme in the frame of DFT to calculate
the equilibrium lattice parameters and the thermodynamic properties of
AlB2 compound with hcp structure. The obtained lattice parameters are in
good agreement with the available experimental data and those calculated by
others. Through the quasi-harmonic Debye model, obtained successfully are
the dependences of the
normalized lattice parameters a/a0 and c/c0 on pressure P, the normalized
primitive cell volume V/V0 on pressure P, the variation of the thermal
expansion α with pressure P and temperature T, as well as the Debye
temperature \ThetaD and the heat capacity CV on pressure P and
temperature T. 相似文献
17.
GUO Yun-dong CAI Da-feng ZHOU Li-ping CHEN Xiang-rong YANG Xiang-dong 《原子与分子物理学报》2006,23(Z1):241-245
For the superconductor MgB2, we have calculated the phonon density of states (DOS), phonon dispersion and Eliashberg function throughout the Brillouin zone (BZ), using an empirical potential model. The calculated values are consistent with the theoretical and experimental values. The calculated results show our empirical potential model is available for MgB2. 相似文献
18.
Lifetimes of rovibrational levels of the long-range I′ 1Πg state of H2 and D2: experiment and theory
The lifetimes of the lowest lying rovibrational levels of the outer well I′ 1Πg state of molecular hydrogen were measured for both H2 and D2. The measurements were made by direct observation of the time-dependent decay of the fluorescence. The observed lifetimes depend on isotopomer and increase with vibrational excitation. The predominant decay route for these levels is fluorescence. Previously published ab initio lifetimes calculated for these states, which accounted for non-adiabatic interactions [J. Chem. Phys. 92, 7461 (1990)], are in good agreement with experiment for H2 but are too long by four or five orders of magnitude for D2. We present new ab initio results at the adiabatic level for the fluorescence lifetimes. The current results are in reasonable agreement with the experimental lifetimes for both H2 and D2. We explain the isotopomer and vibrational dependence of the lifetimes and discuss the neglected interactions and decay pathways. 相似文献
19.
Yogendra Kumar Sharma 《Hyperfine Interactions》1986,28(1-4):1013-1016
57Fe and119Sn Mössbauer and X-ray diffraction studies have been performed at room temperature to establish the presence of various intermediate phases in the quasibinary sections FeSn2-FeSb2 and FeSn2-FeTe2 {i.e. Fe (Sn1–xSbx)2 and Fe (Sn1–xTex)2 for 0x1·0 of the respective ternary systems Fe-Sn-Sb and Fe-Sn-Te at 500°C. Using significantly different Mössbauer hyperfine parameters and the X-ray powder diffraction patterns for each existing stable phase, solid solubility limits and presence of single and multiphase regions have been estimated and are reported. 相似文献
20.
FENGYi-Si YAORi-Sheng ZHANGLi-De 《中国物理快报》2004,21(7):1374-1376
SnO2/SiO2 nanocomposites have been prepared by the soaking-thermal-decomposing method, tin oxide nanoparticles are uniformly dispersed in the mesopores of silica. The optical absorption edge of the obtained nanocomposite presents a redshift compared with bulk tin oxide, With the increasing annealing temperature during the procedure of the sample preparation, the optical absorption edge of the sample moves to shorter wavelength (blueshift). These optical properties can be ascribed to the amorphous structure and band defects of surface layers of the tin oxide nanoparticles. 相似文献