共查询到20条相似文献,搜索用时 296 毫秒
1.
2.
3.
4.
5.
原子核电荷半径Rc所有的实验数据都表明, Rc系统偏离A1/3律, 即随A增大Rc/A1/3系统地递减, 而Rc/Z1/3则比较接近于一个常量. 原子核巨单极共振能量Ex ∝ R-1的大量实验数据也支持这一结论. 根本原因在于A1/3律与同位旋无关, 而Z1/3律已部分反映了同位旋的影响. 基于壳模型, 给出了Z1/3律的微观诠释. 壳模型中质子和中子谐振子势强度参数ωp和ωn的差异, 可以用Z1/3律说明. 基于与Wigner的原子核同位旋多重态质量公式(IMME)相似的理论考虑, 提出了核电荷半径改进的Z1/3律. 相似文献
6.
7.
近年利用超快光谱技术对于4-硝基联苯酚(HO-Bp-NO2)的研究发现,其在单重态和三重态时均会发生光致质子耦合电子转移(PCET)反应. 其瞬态吸收光谱450 nm处有一个独特的尖锐吸收带,但无羟基取代的对硝基联苯(Bp-NO2)未观察到此现象. 本文利用酸性溶液作为外加可控质子供体,通过在强酸(∽10-1 mol/L)和弱酸(∽10-4 mol/L)溶液中的光谱和动力学结果,指认这个新吸收带为开壳层单重态O-Bp-NO2H. 它是HO-Bp-NO2的互变异构体,由三重态HO-Bp-NO2中硝基氧得质子后羟基快速去质子产生. 动力学分析表明,非质子极性溶剂中三重态HO-Bp-NO2与基态母体间还会发生PCET或先质子后电子转移生成自由基·O-Bp-NO2. 这一反应与O-Bp-NO2H竞争,导致其产率较低. 这些结果阐明了三重态HO-Bp-NO2在非质子极性溶剂中的失活机制. 相似文献
8.
9.
利用能量为170MeV的35Cl束流, 通过157Gd(35Cl,4n)熔合蒸发反应研究了188Tl的
高自旋态能级结构. 依据实验结果建立了188Tl基于πh9/2×υi13/2组态的转动带. 根据双奇Tl核能级结构的相似性, 指定了188Tlπh9/2×υi13/2扁椭球转动带的自旋值. 结果表明在188Tl中, πh9/2×υi13/2扁椭球转动带在低自旋区具有旋称反转性质. 利用包含了质子-中子剩余相互作用的准粒子-转子模型, 定性地解释了πh9/2×υi13/2扁椭球转动带的低自旋区旋称反转现象. 相似文献
10.
用正电子淹没寿命谱方法(PALS)研究了质子辐照对空间级硅橡胶KH-L-Y微观结构的影响。试验结果表明,PALS谱所揭示的最长寿命成分的t3, I3及自由体积分数Vf随辐照剂量的增加开始明显下降;而当辐照剂量大于1015cm-2后,随剂量的增加平缓上升。辐照剂量小于1015cm-2时,质子辐照使硅橡胶自由体积减小,分子链间堆砌紧密;辐照剂量大于1015cm-2时,质子辐照使硅橡胶自由体积增大。交联密度及DMA测试结果同样表明,质子辐照在剂量较小时硅橡胶的交联密度及玻璃化转变温度增加,辐照以交联效应为主;而剂量较大时辐照降解占优势。 相似文献
11.
V. L. Litnevsky G. I. Kosenko F. A. Ivanyuk V. V. Pashkevich 《Physics of Atomic Nuclei》2012,75(1):37-44
The effect of the shell structure of colliding nuclei in calculating the entrance channel on the ensuing evolution of the
product system is investigated. The entrance channel is calculated under the assumption of the nose-to-nose orientation of
colliding nuclei. The following three reactions involving nuclei that are deformed in the ground state are considered: 42100Mo + 42100Mo → 84100Po, 42100Mo + 46100Pd → 88210Ra, and 46110Pd + 46110Pd → 92220U. The state of the system at the point of touching is determined by the results obtained by calculating the entrance reaction
channel. The shape of the system is specified by three collective coordinates (deformation parameters). The evolution of collective
coordinates of the system is described in terms of Langevin equations. The potential energy of the system of colliding nuclei
is calculated with allowance for their shell structure. It is shown that allowance for individual features of interacting
nuclei in the entrance channel of the fusion-fission reactions makes it possible to obtain, for the reactions being considered,
cross sections for evaporation-residue formation that are closer to available experimental data than their liquid-drop counterparts. 相似文献
12.
本文叙述了标定德拜-谢乐照相指数的一个新图解法。利用三条低角度衍射线的sin2θ值和该晶体的密度,在A-C空间画一系列条件直线及等原子曲线。三条条件直线和一条等原子曲线的交点直接决定了晶胞的大小和晶胞内所含的原子数或位形单位数。这个方法可应用于四方晶系和六角晶系。
关键词: 相似文献
13.
A study was conducted on the optical absorption spectra ranging from 233 to 285 nm, which were taken in a region close to the source of evaporation of Cu, in low-pressure helium gas of 100 Torr. Eight band systems for Cu2 dimers designated as system 1 through 8 were identified. The spectroscopic constants for the band origins were derived as follows: [vtilde] ≈ 42 200 cm?1 for system 1, [vtilde]00 = 41 604.74cm?1 for system [vtilde]00 = 39 606.70cm?1 for system [vtilde]00 = 38 124.32cm?1 for system 4, [vtilde]00 = 38 048.65 cm?1 for system 5, 98, [vtilde]00 = 36 834.22cm?1 for system 6, [vtilde]00 = 36 341.55 cm?1 for system 7 and [vtilde]00 = 36 174.99cm?1 for system 8. For all cases in which vibrational constants of the lower state could be determined, it was found that the transition originated from the ground state of Cu2. 相似文献
14.
The relative probabilities for the radiative de-excitation 2p+ → ls+ versus 2γ-annihilation for the hdot; ns2np62p+, 2P state of the [X-e+] system with X = F, Cl, Br, and I are presented. It is shown that a positron captured into a 2p+ orbital undergoes annihilation with electrons of the system instead of radiative transition to the ground state of the [X-e+] system. 相似文献
15.
The asymmetric 3He4He2 three-atomic system is studied on the basis of a hard-core version of the Faddeev differential equations. Binding energy and scattering observables for this system are compared to previous results for the symmetric 4He3 problem. 相似文献
16.
K.K. Innes S.J. Jackling T.W. Tolbert 《Journal of Quantitative Spectroscopy & Radiative Transfer》1976,16(5):443-450
Line positions and widths of the B3Πo+u?X1Σ+g electronic transitions of chlorine and bromine gases are measured in absorption as functions of pressure by means of a scanning Fabry-Perot interferometer spectrometer (resolving power > 106). No dependences on quantum numbers are detected. Deconvolutions of measured full-widths-at-half-maxima (FWHM) reveal collision broadening for pressures between 1 and 225 torr. The ratio of self-broadening to shift is always less than that expected for a van der Waals interaction in the impact approximation, namely -2.77. Accordingly, the Lennard-Jones potential is used to determine the effect of the electronic transitions on C6 and C12, and there are found 14 and 6% changes in C6 for Cl2 and Br2, respectively. If, instead, one uses the self-broadening only, and a pure van der Waals interaction, the changes are 6 and 5%. Because the effects are in either model unexpectedly small, comparisons are made with less complete measurements (from the literature) for self-broadening in I2, the B1Σ+g?X3Σ-g system of O2 and the B′Σ+g?X1Σ+g system of HD, and for foreign-gas broadening in the A1Π?X1Σ system of A1H and the A̋1A2(π1, n)?X̋1A1 system of H2CO as well as the HD system. 相似文献
17.
After the discussion of the main reaction mechanisms as ionization, dissociation, dissociative recombination, ion-molecule-reactions and chemical reactions between neutral particles a system of balance equations for the ions H+, H2+, H3+, and H5+, for the atoms, for the mixture of neutral particles, for charge neutrality and the discharge current is given in the framework of the diffusion theory. The numerical method for the solution of this system is explained. In the following parts of this paper detailed results of the numerical calculation will be dicussed in comparison with some experimental investigations. 相似文献
18.
本文通过对11B核磁共振(11B-NMR)、红外光谱等实验方法,研究了LiF-LiCl-B2O3三元系统玻璃的结构和离子导电性,着重于F-离子在玻璃网络中所起的作用,以及F-,Cl-和Li+离子对导电率的影响。LiF-LiCl-B2O3三元系统玻璃,随LiF含量的增加,B由三角体向四面体变化,从而F-离子进入网络,使玻璃结构由[B2O3]三角体层状结构向三维空间延展,形成了含有[BO3F]基团的三维空间网络,Cl-离子以游离的离子存在于网络中,起着松散网络的作用,对提高电导率有利,而Li+离子作为传导离子,对电导率的贡献是主要的。本系统玻璃的电导率是随LiF,LiCl含量的增加而增大,在300℃时测得电导率σ=6.12×10-4Ω-1·cm-1。
关键词: 相似文献
19.
Abstract In acetonitrile solutions, the exchange reaction is bimolecular in the Tl+ + 18C6 system, while in the Tl+ + pentaglyme system the associative-dissociative and the bimolecular mechanisms coexist at room temperature and the bimolecular exchange reaction dominates at 263° K. For the bimolecular mechanism in the case of Tl+ + 18C6 and the associative-dissociative mechanism in the case of Tl+ + pentaglyme, the activation energies of the exchange reactions change with temperature. At 298° K, in the Tl+ + 18C6 system the activation energy for the bimolecular exchange reaction is ≈ 2 kcal.mol?1 and exchange rate constant (k1) is (4.1 ± 0.1) × 107 s?1mol?1; in the Tl+ + pentaglyme system, the activation energy for the associative-dissociative exchange reaction is ≈ 5 kcal mol?1 and the decomplexation rate constant (k?2) is (2.2 ± 0.4) X 105 s?1. The activation energy for the bimolecular exchange in the Tl+ + pentaglyme system was determined to be 3.00 ± 0.05 kcal.mol?1 and the exchange rate constant (3.0 ± 0.1) X 108 s?1 mol?1. 相似文献
20.
Francesco Cramarossa Giovanni Ferraro Ettore Molinari 《Journal of Quantitative Spectroscopy & Radiative Transfer》1977,18(5):471-479
Simultaneous vibro-rotational analyses have been carried out for the second positive system (SPS) of N2 (C3Пu ? B3Пg), for the violet system (VS) of CN (B2Σ ? X2Σ) and for the Swan system (SS) of C2 (d3Пg ? a3Пu), emitted by 35 MHz electrical discharges, containing N2, H2 and CH4 flowing mixture s, in the 5–40 torr pressure range and at 1–10 Wcm-3 power densities. The results are consistent with a Boltzman distribution for the rotational levels, but they show a deviation from this law for upper vibrational levels of CN and C2. 相似文献