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1.
使用对称性匹配簇-组态相互作用方法首次计算了Li2分子自旋一致激发态a3Σ+u和b3Πu的离解能、平衡几何及其谐振频率。使用最小二乘法、利用Murrell-Sorbie函数形式拟合出了Li2分子三重态的第一激发态a3Σ+u 和第二激发态b3Πu的完整势能函数,并计算了这两个态的光谱常数 (Be, αe, ωe 和 ωeχe) 和力常数 (f2, f3和f4)。得到了Murrell-Sorbie函数形式既适用于基态、又适用于激发态的结论。将计算得到的激发态(a3Σ+u和b3Πu)的离解能、平衡几何及其谐振频率与实验结果及其它理论计算结果进行了比较。从比较的结果中可以清楚地看出,本文的计算结果在计算精度方面有很大的改进。  相似文献   

2.
李心梅  阮亚平  钟志萍 《物理学报》2012,61(2):023104-223
本文在多通道量子数亏损理论(MQDT)框架下,利用相对论多通道理论(RMCT),分别在冻结实近似、 考虑Δl=-1的偶极极化效应、Δl=+1的偶极极化效应、Δl=± 1的偶极极化效应、伸缩模效应以及同时考虑偶极极化效应和伸缩模效应等不同层次近似下,系统地计算了碱金属Li, Na, K, Rb, Cs和Fr七个里德伯系列的能级,即ns2S1/2, np2P1/2, np2P3/2, nd2D3/2, nd2D5/2, nf2F5/2nf2F7/2.计算结果表明,电子关联效应对碱金属原子的里德伯能级的影响很大.总的来说,偶极极化效应比伸缩模效应重要,而在偶极极化效应中, Δl = + 1的偶极极化效应比Δl = - 1的偶极极化效应重要.但对于Na的ns2S1/2,(nd2D3/2,nd2D5/2)里德伯系列的能级,和Li的(np2P1/2,np2P3/2)里德伯系列的能级,是伸缩模效应比较重要.  相似文献   

3.
用密度泛函B3LYP/lanl2dz方法研究了S2分子与多孔硅中SiHx (x=1, 2, 3)的相互作用, 构建了表面掺杂有CH3,Si-O-Si和OH结构的多孔硅模型. 当S2分子处于模型不同位置时,通过分析结合能和电子迁移发现S2分子与SiHx (x=1, 2, 3)的相互作用强于S2分子与CH3和OH的相互作用. 利用过渡态理论研究了Si2H6+S2→H3SiH2SiS+HS反应,得到反应势垒为50.2 kJ/mol.  相似文献   

4.
使用密度泛函理论B3LYP和B3P86,以及组态相互作用方法CCSD(T)和QCISD, 利用多个基组对7Li2(X1Σ+g)分子的平衡核间距(Re)、谐振频率(ωe)和离解能(De)进行了计算, 发现在CCSD(T)/cc-PVQZ理论水平下得到的结果(Re相似文献   

5.
本文基于北京正负电子对撞机(BEPC)上北京谱仪(BES)所收集到的2.5×106J/ψ重建刻度后的事例,研究了强子衰变道J/ψ→ωf2(1270),f2(1270)→π+π所揭示出的共振态f2(1270)的性质,测量了它的质量、宽度和分支比,利用最大似然法对角分布进行了拟合,给出自旋宇称为2++,首次得到螺旋度振幅比为x=0.99±0.29; y=-0.24±0.17; z1=0.90±0.57;z2=0.56±0.22.  相似文献   

6.
韩晓琴  肖夏杰  刘玉芳 《物理学报》2012,61(16):163101-163101
采用Gassian09程序包中的多种方法对OH, OCI, HOCI分子的基态结构进行优化计算, 优选出QCISD/6-311G(2df), B3P86/6-311+G(2df)方法分别对OH(X2), OCI(X2)分子进行计算, 得到平衡核间距ROH=0.09696 nm, ROCI=0.1569 nm, 谐振频率ω(OH)=3745.37 cm-1, ω(OCI)=892.046 cm-1, 与实验结果非常符合. 用Murrell-Sorbie势能函数对OH和OCI分子的扫描势能点进行拟合, 其扫描点都与四参数Murrell-Sorbie函数拟合曲线符合得很好.优选出QCISD(T)/D95(df, pd)方法对HOCI分子进行计算, 得到基态为X1A', 键长ROH =0.0966 nm, 键角∠HOCI=102.3°, 谐振频率ω1(a1)=738.69 cm-1, ω2(b2)=1260.25 cm-1, 离解能De=2.24eV. 通过比较发现这些结果与实验值符合得很好,并优于文献报道的结果. 随后计算出了力常数, 在此基础上,推导出HOCI分子的多体展式势能函数.报道了HOCI分子对称伸缩振动势能图中在H+OCI →HOCI反应通道上有一鞍点, H原子需要越过1.74eV的能垒才能生成HOCI的稳定结构, 在Cl+OH→HOCI通道上不存在明显势垒, 容易形成稳定的HOCI分子.  相似文献   

7.
杨善德 《物理学报》1965,21(8):1522-1532
本文对2s1/2-1d3/2壳层原子核(A=30—40)能谱作了系统分析,计算仅限于由2s1/2和1d3/2支壳层产生的情态,但考虑了它们之间的全部组态混合效应。计算是采用多粒子壳模型的Talmi方法,将二体矩阵元当作参数,其值由实验确定。文中详细分析了Si30,Si31,P30,P31,P32,S32,Ar37,Ar38,K38等原子核能谱,理论与实验符合颇好。  相似文献   

8.
BES合作组 《中国物理 C》1996,20(12):1057-1067
利用北京谱仪在北京正负电子对撞机上采集的350万(2S)事例,通过ψ(2S)→γπ+π和γK+K反应道测量了χc0的总宽度.由Monte Carlo模拟给出的质量分辨函数,利用拟合χc2谱形得到的质量分辨作标定后,用于χc0宽度的拟合,得到χc0的宽度为(15.0)MeV.同时定出了χcJ(J=0,2)到π+π-+K的衰变分支比.结果为B(χc0→π+π)=(4.27±0.23±0.60)×10-3,B(χc0→K+K)=(3.44±0.21±0.47)×10-3,B(χc2→π+π)=(1.52±0.17±0.29)×10-3 和 B(χc2→K+K)=(5.2±1.1±1.8)×10-4,其中第一项误差为统计误差,第二项为系统误差.  相似文献   

9.
熊晓玲  魏洪源  陈文 《物理学报》2012,61(1):013401
应用群论及原子分子反应静力学方法推导了TiN分子基态(X2Σ )的离解极限. 采用不同的密度泛函方法,包括BP86, B3P86, B3LYP, B3PW91, 分别选用不同的基组对TiN分子基态进行结构优化计算.通过比较得出使用BP86方法, 对N原子使用D95V++(d,P)基组和Ti原子使用6-311++G**基组时,计算得到的平衡几何结构、 分子离解能和谐振频率与实验值符合得最好. 并采用最小二乘法拟合改进的Murrell-Sorbie函数得到了相应电子态的完整势能函数. 计算得到的光谱常数与实验光谱数据符合得很好.  相似文献   

10.
本文使用OH激光诱导荧光方法研究了结构最简单的克里奇中间体CH2OO和CF3CF=CF2的反应动力学. 在压强为10 Torr条件下,测量了温度在283,298,308和318 K的反应速率常数,分别为(1.45±0.14)×10-13,(1.18±0.11)×10-13,(1.11±0.08)×10-13和(1.04±0.08)×10-13 cm3·molecule-1·s-1. 根据阿伦尼乌斯方程,获得该反应的活化能为(-1.66±0.21) kcal/mol. 在6.3∽70 torr压力范围内,未观察到该反应的速率常数存在压力相关.  相似文献   

11.
锐钛矿相纳米TiO2晶体生长动力学及生长过程控制   总被引:1,自引:0,他引:1       下载免费PDF全文
研究了采用溶胶-凝胶法经由前驱物钛酸四异丙酯水解制备纳米TiO2结构相变及锐钛矿晶体生长动力学过程. 研究结果表明,在酸性条件下水解,由于高压热处理温度的变化导致锐钛矿向金红石相的结构相变,锐钛矿相纳米TiO2生长活化能在250℃以下和以上分别为(15.8±4.5)kJ/mol和(80.2±1.0)kJ/mol;而在碱性条件下水解的活化能值为(3.5±0.4)kJ/mol. 在不发生结构相变的条件下,酸性水解条件下锐钛矿相纳米TiO2生长速 关键词: 2')" href="#">纳米TiO2 锐钛矿 生长动力学 溶胶-凝胶法  相似文献   

12.
An approximate theory of dipolar relaxation by the soft modes of magnetic vacancies and dislocations gives 23 and 1 for the power-law exponents of T2, while proton T1 and EPR linewidth measurements yield 0.67 ± 0.04 and 1.0 ± 0.1.  相似文献   

13.
Heat capacities of [Fe(phen)2(NCS)2] and [Fe(phen)2(NCSe)2] were measured between 135 and 375 K. A heat capacity anomaly due to the spin-transition from low-spin 1A1 to high-spin π2 electronic ground state was found at 176·29 K for the SCN-compound and at 231·26 K for the SeCN-compound, respectively. Enthalpy and entropy of transition were determined to be ΔH = 8·60 ± 0·14 kJ mol?1 and ΔS = 48·78 ± 0·71 J K?1 mol?1 for the SCN-compound and ΔH = 11·60 ± 0·44 kJ mol?1 and ΔS = 51·22 ± 2·33 J K?1 mol?1 for the SeCN-compound. To account for much larger value of ΔS compared with the magnetic contribution, we suggest that there is significant coupling between electronic state and phonon system. We also present a phenomenological theory based on heterophase fluctuation. Gross aspects of magnetic, spectroscopic, and thermal behaviors were satisfactorily accounted for by this model. To examine closely the transition process, infrared spectra were recorded as a function of temperature in the range 4000 ? 30 cm?1. The spectra revealed clearly the coexistence of the 1A1, and the 5T2 ground states around Tc.  相似文献   

14.
Coherent Stokes and anti-Stokes Raman scattering are used to study the ν1 and ν2 spectral band profiles of UF6 and SF6. Most of the observed SF6 “hot” bands are assigned, leading to evaluations of the anharmonicity constants Xij: X12 = ?(2.80 ± 0.30) cm?1, X14 = ?(1.00 ± 0.15) cm?1, X15 = ?(1.00 ± 0.15) cm?1. For UF6, a tentative assignment of the “hot” bands is made: X12 = ?(1.80 ± 0.30) cm?1, X13 = ?(1.60 ± 0.30) cm?1, X14 = ?(0.20 ± 0.10) cm?1, X15 = ?(0.25 ± 0.10) cm?1, and X16 = ?(0.10 ± 0.05) cm?1. Parameters such as the vibration-rotation coupling constants are determined. For SF6: α = (7 ± 2) × 10?5 cm?1 for the ν2 band and α = ?(1.02 ± 0.01) 10?4 cm?1 for the ν1 band. The calculated spectral profiles of the coherent Stokes or anti-Stokes spectra, which are in good agreement with experimental results, give values for the resonant and nonresonant parts of the susceptibility in both molecules. They also show, in some cases, the influence of neighboring combination bands.  相似文献   

15.
A small polycrystalline ingot sample of NpCo2Si2 (weight ≈ 1.5 g) has been studied by neutron diffration between 2 and 160 K on the multi-detector D1B of ILL, Grenoble. At 100 K, the crystal structure is body-centered tetragonal (space group 14/mmm) with a = 3.886 Å and c =9.649 Å. Below TN = (44 ± 2) K, seven superlattice lines are observed which correspond to a simple tetragonal lattice with lattice constants as above. They are consistent with a type I antiferromagnetic structure of the Np (2a) sublattice, with (001) ferromagnetic sheets coupled antiferromagnetically according to the sequence +-+-. At 6 K, the neptunium moment obtained from the diffracted intensities is: (1.48 ± 0.20)μuB, and makes an angle 52° ± 15° with the c axis. The cobalt moment is certainly smallet than 0.3μuB. The Np moment correlates well with the 237Np hyperfine field deduced from Mos?sbauer spectroscopy; the sublattice magnetization-temoperature curve follows very well the J=12 brillouin curve. The magnetism is therefore probably of lovalized character in this compound. An isomorphous sample of NpCu2Si2 (a = 3.990 Å c = 9.920 Å) was shown to be ferromagnetic below (41 ± 2) K, with the Np moment [1.5 ± 0.2)μuB] aligned along the c axis.  相似文献   

16.
A new compound, Na4ZrSi3O10, belonging to the ternary system Na2O-SiO2-ZrO2 is presented. Based on X-ray powder methods, it is assigned monoclinic symmetry with the probable group C 2/c. The ionic conductivity was found to be 4 x 10-3Ω-1cm-1 at 300°C and the activation energy for ionic motion is 42 kJ/mol.  相似文献   

17.
用时间分辨傅立叶变换红外发射光谱(TR-FTIR)和G3MP2//B3LYP/6-311G(d,p)水平的电子结构计算研究了环境化学中重要的二氯代乙烯自由基C2HCl2和O2分子的基元反应通道和机理. 通过0.5 cm-1高分辨的TR-FTIR发射光谱观察到三种振动激发态产物CO2、CO和HCl,由光谱拟合得到CO和HCl的振动态分布,结合电子结构计算的反应势能曲线,提出反应机理和能量上最可能的反  相似文献   

18.
The electrical and electrochemical properties of the solid ionic conductor UO2HPO4·3H2O were investigated within the temperature range from room temperature up to 673 K. The conductivity of a nondehydrated sample within the temperature range from 303 K (6.5 × 10-3 S/m) to 350 K (2.5 × 10-2 S/m), with the activation energy of 23 kJ/mol, is a consequence of the presence of crystal water, and originates, mostly, from the fast movement of protons across the network of molecules of water in a tunneling mechanism pattern. When heated, the conductor loses crystal water, which leads to a final change in the nature of the conductor and in the conductivity mechanism. The conductivity of the dehydrated salt UO2HPO4 (2.5 × 10-4 S/m at 488 K), with the activation energy 44.04 kJ/mol, is considerably lower than the one mentioned above and can be attributed, to a great extent, to the movement of protons, most likely by a tunneling mechanism, through the less favourable structure formed by phosphate groups of the dehydrated salt. On being heated above 623 K for a certain time, the acid phosphate transforms into pyrophosphate, the conductivity of which is lower than that mentioned above. By means of electrochemical methods, the electrode processes were studied. It has been shown that H+ and UO2+ ions are reduced at the cathode, while the phosphate groups oxidize at the anode and O2 is evolved.  相似文献   

19.
The results of our experimental study of the kinetics of formation of O2(1Σ) molecules in energy-exchange reactions O2(1Δ) + I(5 p,2 P 1/2) and O2(a,1Δ) + O2(a,1Δ) are presented. The ratio of rate constants was obtained for these reactions (4800 ± 300). Setting the rate constant of the deactivation of O2(1Σ) molecules on CO2 molecules at 4.1 · 10–13 cm3/s, we evaluated the rate constants for these reactions at a temperature of approximately 330 K: (1.7 ± 0.2) · 10−13 and (3.6 ± 0.5) · 10−17 cm3/s, respectively.  相似文献   

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