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31.
采用密度泛函B3P86和组态相互作用方法在6-311G**基组水平上计算了二氧化硅分子从基态到前5个激发态的跃迁波长、振子强度、自发辐射系数An0和吸收系数B0n(n=1—5).研究了外电场对二氧化硅分子激发态的影响规律. 结果表明,随外电场强度增大,最高占据轨道与最低空轨道能隙变小,占据轨道的电子易于激发至空轨道. 因而在外场作用下分子易于激发.
关键词:
2')" href="#">SiO2
激发态
外电场 相似文献
32.
采用 B3P86方法计算了C6H6在外电场作用下分子系统的能量及分子轨道能级、谐振频率、CH键离解能和极化率等分子特性;通过跃迁矩阵元计算了各激发态的激发能,吸收及自发辐射系数,从而进一步分析了苯分子的外场效应.对于高分子化合物尤其是具有苯环结构的有机高分子化合物的外场作用特性的研究具有参考价值. 相似文献
33.
采用密度泛函DFT中的B3P86方法,选用6-311g**基组,对平面环状碳团簇Cn(n=6,10,13,24)的振转能级特性进行了研究.结果表明,碳团簇环状结构的转动能谱恰好处于微波区域,且随碳环面积增大而向低频方向移动.同时对环状碳团簇Cn的能级分布,最高占据轨道HOMO,最低空轨道LUMO及能隙HLGs进行了研究.最后指出,利用环状碳团簇转动能谱位于微波区域的特性,设计出具有低频吸收功能的新型吸波和电磁屏蔽材料. 相似文献
34.
采用密度泛函DFT中的 B3LYP 方法,选择LANL2DZ基组,对Aun(n=2—9)小团簇的各种可能结构进行优化,得到了它们的基态平衡结构并计算出其原子化能.研究表明:随着团簇尺寸的增大,单个原子的平均原子化能逐渐增大.同时分析了团簇的能级分布、最高占据轨道与最低空轨道之间形成的能级间隙.计算出了电子亲和能和电离势,计算值与实验值非常接近.最后分析了费米能级、电子亲和能和电离势形成“奇-偶”振荡效应的原因.
关键词:
Au团簇
平衡几何结构
能隙
电子性质 相似文献
35.
采用密度泛函B3P86方法在6-311++G(d, p)基组水平上优化得到了沿分子轴方向不同外电场(0-0.04 a.u.)作用下, 甲基乙烯基硅酮分子的基态电子状态、几何结构、电偶极矩和分子总能量. 在优化构型下利用杂化CIS-DFT方法(CIS-B3P86)研究了同样外电场条件下对甲基乙烯基硅酮的激发能和振子强度的影响. 计算结果表明, 分子几何构型与电场大小呈现强烈的依赖关系, 分子偶极矩μ随电场的增加先减小后急剧增大. 电场为零时, 分子总能量为-483.5532137 a.u., 随着电场增加, 能量升高, 在F=0.02 a.u.时达到最大值-483.5393952 a.u., 此后, 继续增大电场系统总能量则开始降低. 激发能随电场增加急剧减小, 表明在电场作用下, 分子易于激发和离解. 相似文献
36.
37.
High adsorption and separation performance ofCO2 over N2 in azo-based (N=N) pillar[6]arene supramolecular organic frameworks 下载免费PDF全文
Yong-Chao Jiang 《中国物理 B》2021,30(11):118105-118105
Azo-based pillar[6]arene supramolecular organic frameworks are reported for CO2 and N2 adsorption and separation by density functional theory and grand canonical Monte-Carlo simulation. Azo-based pillar[6]arene provides suitable environment for CO2 adsorption and selectivity. The adsorption and selectivity results show that introducing azo groups can effectively improve CO2 adsorption and selectivity over N2, and both CO2 adsorption and CO2 selectivity over N2 follow the sequence pillar[6]arene_N4 > pillar[6]arene_N2 > pillar[6]arene. Pillar[6]arene_N4 exhibits CO2 adsorption capacity of ~ 1.36 mmol/g, and superior selectivity of CO2 over N2 of ~ 116.75 with equal molar fraction at 1 bar (1 bar=105 Pa) and 298 K. Interaction analysis confirms that both the Coulomb and van der Waals interactions between CO2 with pillar[6]arene frameworks are greater than that of N2. The stronger affinity of CO2 with pillar[6]arene_N4 than other structures and the larger isosteric heat differences between CO2 and N2 rendered pillar[6]arene_N4 to present the high CO2 adsorption capacity and high CO2 selectivity over N2. Our results highlight the potential of azo-functionalization as an excellent means to improve pillar[6]arene for CO2 capture and separation. 相似文献
38.
First principles study on geometric and electronic properties of two-dimensional Nb2CTx MXenes 下载免费PDF全文
Guoliang Xu 《中国物理 B》2022,31(3):37304-037304
MXenes are a new type of two-dimensional carbides with rich physical and chemical properties. The physics of MXenes, and thus the applications, are dominated by surface functional groups. Herein, the effects of different terminations (O, S, Se, Te) on the geometric and electronic properties of Nb2C MXenes were studied via density functional theory (DFT) calculations. Three adsorption sites were examined to determine the most stable configurations. The results showed that both the types and the positions of surface functional groups influence the geometric stability and physical characters of Nb2C. The S and Se terminations make the Nb2C MXenes to be semiconductor, while Nb2C MXenes with other terminations (O, Te) are conductor. The electron location function, density of states, Bader charge distribution, and the projected crystal orbital Hamilton population were conducted to explain the origin of adsorption stability and electronic nature difference. Our results provide a fundamental understanding about the effects of surface terminations on the intrinsic stability and electronic properties of Nb2C MXenes. 相似文献
39.
The first-principles plane-wave pseudopotential method using the generalized gradient approximation within the framework of density functional theory is applied to anaylse the equilibrium lattice parameters, six independent elastic constants, bulk moduli, thermal expansions and heat capacities of MoSi2. The quasi-harmonic Debye model, using a set of total energy versus cell volume obtained with the plane-wave pseudopotential method, is applied to the study of the elastic properties, thermodynamic properties and vibrational effects. The calculated zero pressure elastic constants are in overall good agreement with the experimental data. The calculated heat capacities and the thermal expansions agree well with the observed values under ambient conditions and those calculated by others. The results show that the temperature has hardly any effect under high pressure. 相似文献
40.
曲率对机翼边界层二次失稳影响 总被引:1,自引:0,他引:1
采用非线性抛物化扰动方程(NPSE)计算了层流机翼NLF0415(2)在几个工况下横流涡的非线性发展, 应用Floquet理论分析了横流涡的二次失稳. 较系统地分析了后掠机翼在多种参数下表面曲率对其流动稳定性的影响. Haynes证明曲率对于横流在线性稳定性计算(LST)和非线性抛物化扰动方程计算中(NPSE)都起着非常明显的稳定作用; 然而, 该文计算结果表明, 曲率在二次失稳计算中影响不大. 相似文献