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1.
采用杂化密度泛函(DFT)之B3LYP/6-311G**方法研究了NxHy-Fe(x=0~2,y=0~3)配位簇的几何结构和振动光谱,讨论了在纯铁催化剂上,氮分子和氢分子逐步合成氨的反应机理,结果表明,合成氨过程可能经历N2和N2H2物种,在优化结构的基础上,计算了各个模型的振动频率并解释了有关实验结果。  相似文献   

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基于ab initio势能面(KBNN PES)[1],用耦合通道超球坐标理论研究了碰撞能等于0.5 eV时H D2(v=0,j=0)的积分,微分截面.对于反应性碰撞,计算的积分截面表明由于深势阱的存在使得这一绝热反应产物的分布表现出一种近似的统计行为.计算的微分截面反映该体系存在着长寿命的中间络合物;对于非反应性碰撞(传能过程),平动—平动传能过程更有效,且其积分截面随着转动量子数的增大而显著减少.通过反应性碰撞和非反应性碰撞积分截面的比较,发现在低能碰撞情况,非反应性碰撞更容易进行.  相似文献   

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<正>Ω~-I(J~P)=0(3/2~+)Status:****The unambiguous discovery in both production and decay was by BARNES 64.The quantum numbers follow from the assignment of the particle to the baryon decuplet.DEUTSCHMANN 78 and BAUBILLIER 78 rule out J=1/2 and find consistency with J=3/2.AUBERT.BE 06 finds from the decay angular distributions ofΞ_c~0→Ω~-K~+andΩ_(c~0)→Ω~-K~+that J=3/2;this depends on the spins of theΞ_c~0 andΩ_c~0 being J=1/2,their supposed values.We have omitted some results that have been superseded by later experiments.See our earlier editions.  相似文献   

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Pressure broadening widths and pressure-induced frequency shifts for the hydroxyl radical Q11([see full textsee full text]), Q21([see full textsee full text]), Q11(2), Q21(2) absorption lines in the A band at ca. 308 nm have been determined in the presence of a variety of gases (N2, Ar, Ne and He). Hydroxyl radicals were formed using either a microwave discharge or a vacuum ultra-violet photolysis of water vapour and were detected using direct absorption spectroscopy with a bandwidth normalised noise equivalent absorption sensitivity of 5 ×10-5 Hz-1/2. A tunable external cavity diode laser at 835 nm and a single-frequency continuous-wave intracavity frequency-doubled diode laser at 488 nm were used to produce tunable continuous-wave light at 308 nm by sum-frequency generation in a -BaB2O4 crystal.  相似文献   

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《Nuclear Physics B》2001,604(3):537-550
Using explicit results for the four-point correlation functions of the Wess–Zumino–Novikov–Witten (WZNW) model we discuss the conformal embedding osp(4|4)1 = osp(2|2)−2 ⊕ su(2)0. This embedding has emerged in Bernard and LeClair's recent paper cond-mat/003075. Given that the osp(4|4)1 WZNW model is a free theory with power law correlation functions, whereas the su(2)0 and osp(2|2)−2 models are CFTs with logarithmic correlation functions, one immediately wonders whether or not it is possible to combine these logarithms and obtain simple power laws. Indeed, this very concern has been raised in a revised version of cond-mat/003075. In this paper we demonstrate how one may recover the free field behaviour from a braiding of the solutions of the su(2)0 and osp(2|2)−2 Knizhnik–Zamolodchikov equations. We do this by implementing a procedure analogous to the conformal bootstrap programme Nucl. Phys. B 241 (1984) 333. Our ability to recover such simple behaviour relies on a remarkable identity in the theory of elliptic integrals known as Legendre's relation.  相似文献   

8.
Intensities for the γ(A2Σ+?→?X2Π), ε(D2Σ+?→?X2Π) and (D2Σ+?→?A2Σ+) bands for NO have been calculated using the Molecular Quantum Defect Orbital (MQDO) methodology. Radiative lifetimes for the A2Σ+ and D2Σ+ vibrational Rydberg states have also been determined. The present results are in excellent accord with measurements available in the literature. Additionally, predictions for a number of unknown intensities and radiative lifetimes are made, given their potential usefulness.  相似文献   

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借助光子导出了E=mc2和m=m01-v2/c2.  相似文献   

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本文采用法拉弟效应的激光磁共振光谱技术,研究了-氧化氮分子14N16OX2Π3/2R(1.5)v=0→1和同位素分子15N16OX2Π3/2Q(1.5)v=0→1跃迁的FLMR光谱,实验给出了样品浓度和信号强度之间的关系及调制磁场强度与FLMR信号强度之间的关系。  相似文献   

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用原子分子反应静力学原理推导出CrHn(n =0,+1,+2)的电子状态及其离解极限.对H原子采用6-311++G**基组,对Cr原子采用SVP(split valence polarization)全电子基组,用B3PW91方法计算了它们的平衡几何、电子状态,在此基础上分别计算CrH, CrH+的Murrell-Sorbie解析势能函数和CrH2+的解析势能函数及其对应的力常数、光谱参数,理论计算值与实验值和文献计算值符合较好.从离解极限和通道解释了不同的势能函数形状.计算表明:CrH+的势能曲线均具有对应于稳定平衡结构的极小点,说明CrH+可稳定存在.而CrH2+离子的势能曲线对应于不稳定的排斥态,说明CrH2+是不稳定的.  相似文献   

13.
利用1A′态的势能面[ Ho et al., J. Chem. Phys. 116, 4124 (2002)],采用准经典轨线方法研究了在不同碰撞能条件下,S(1D) +H2(v=0, j=0)→SH+H反应的立体动力学性质. 通过计算得到了描述反应物速度矢量k与产物的转动角动量矢量j′这两个矢量相关的分布函数P(r)、描述反应物速度矢量k、产物速度矢量k′与产物的转动角动量矢量j′这三个矢量相关的二面角分布函数P(r)以及描述反应产物角动量极化的分布函数P(r,r).计算结果表明产物的转动角动量矢量j′在空间具有明显的定向和取向效应,并且产物的转动角动量具有强烈的极化. 另外,计算结果还表明这些立体动力学性质对碰撞能非常敏感.  相似文献   

14.
利用1A′态的势能面[ Ho et al., J. Chem. Phys. 116, 4124 (2002)],采用准经典轨线方法研究了在不同碰撞能条件下,S(1D) +H2(v=0, j=0)→SH+H反应的立体动力学性质. 通过计算得到了描述反应物速度矢量k与产物的转动角动量矢量j′这两个矢量相关的分布函数P(r)、描述反应物速度矢量k、产物速度矢量k′与产物的转动角动量矢量j′这三个矢量相关的二面角分布函数P(r)以及描述反应产物角动量极化的分布函数P(r,r).计算结果表明产物的转动角动量矢量j′在空间具有明显的定向和取向效应,并且产物的转动角动量具有强烈的极化. 另外,计算结果还表明这些立体动力学性质对碰撞能非常敏感.  相似文献   

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基于密度泛函理论的第一性原理计算,我们研究了CrO2块体以及其(1 0 0)和(0 0 1)表面的磁性和电子结构。CrO2(1 0 0)表面中表面层Cr原子向内收缩,而(0 0 1)表面中的表面层Cr原子却向外伸展;越往内层,原子驰豫幅度越小。由于表面效应。表面层原子的磁矩有了大幅的提升,其中(1 0 0)表面中表面层Cr原子的磁矩最高,为3.03μB。电子结构计算表明,CrO2 (1 0 0)和(0 0 1)表面均保持了块体中良好的半金属性,并且半金属带隙在(1 0 0)表面中受到了进一步的拓宽,因此具有更稳定的半金属性  相似文献   

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利用高温高压手段合成了系列Nb缺位的Nb1-xB2超导体.在x=0~0.7的范围内都可得到单相的AlB2结构样品.整配比的NbB2中未发现超导电性,当x大于零后,可观察到超导电性出现.最高转变温度Tc接近9K.  相似文献   

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本文使用交叉分子束方法研究了氟原子和振动激发态氖分子D_2(v=1,j=0)的反应.使用受激拉曼抽运的方法制备了振动激发的D_2分子.实验中未观测到来自于旋轨耦合激发态氟原子F*(~2P_(1/2))与振动激发态D_2分子的贡献.观测到来自于旋轨耦合基态氟原子F(~2P_(3/2))和振动激发态D_2的反应信号,相应的产物DF分子布居于u'=2,3,4,5振动态上.与振动基态反应F+D_2(v=1,j=0)相比,振动激发态反应F+D_2(v=1,j=0)生成的DF产物转动分布更"热".获得了振动激发反应的四个碰撞能在0.32至2.62 kcal/mol范围内的微分反应截面.在最低的碰撞能0.32 kcal/mol下,所有振动态的DF产物都以后向散射为主.随着碰撞能的增加,DF产物的角分布逐渐从后向转移到侧向.测量了DF(v'=5)产物的前向微分散射截面随碰撞能变化的曲线.前向散射的DF(v'=5)信号出现于1.0 kcal/mol.在2.62 kcal/mol碰撞能下DF(v'=5)主要为前向散射.  相似文献   

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使用粒子群优化算法结合从头算方法得到了羟基水团簇OH~n(H_2O)_3(n=0,±1)的低能结构,并对考虑零点能后最稳定的团簇的成键、分子轨道和红外性质进行了对比研究.对最高占据轨道进行键序分析表明:阴离子团簇中的外来电子占据了羟基中的氧原子的空轨道,自由基型团簇中的部分电子从水分子转移到了羟基上,阳离子团簇中形成了很强的氧氧键.对这些团簇的红外谱进行了计算和分析,这将为相关实验提供理论参考.  相似文献   

19.
Yong Zhang 《中国物理 B》2022,31(11):113101-113101
A global potential energy surface (PES) of the ground state of SiH$_{2}^{+}$ system is built by using neural network method based on 18223 ab initio points. The topographic properties of PES are presented and compared with previous theoretical and experimental studies. The results indicate that the spectroscopic parameters obtained from the new PES are in good agreement with the experimental data. In order to further verify the validity of the new PES, a test dynamics calculation of the Si$^{+} +$ H$_{2}$ ($v_0 = 2, j_{0} = 0$) $\to $ H $+$ SiH$^{+}$ reaction has been carried out by using the time-dependent wave packet method. The integral cross sections and rate constants are computed for the title reaction. The reasonable dynamical behavior indicates that the newly constructed PES is suitable for relevant dynamics investigations.  相似文献   

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