共查询到20条相似文献,搜索用时 140 毫秒
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勾秉聪 《原子与分子物理学报》1997,14(4):505-510
采用马鞍点变分方法和复数转动技术,计算了类锂离子2s2p2p2S三激发共振态的能量,并运用截断变分方法得到能量改进量,以及计算了相对论效应、质量极化效应,从而获得了高精度的能量计算值。还计算了该系统的Auger宽度,位移和辐射跃迁率。 相似文献
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在屏蔽理论和多体微扰理论的基础上,文中提出了一种新的计算等电子序列离子基组态能量的方法,用该方法和作者设计的FORTRAN程序,计算了LiⅠ等电子序列离子 (3≤Z≤20)基组态能量,计算结果与已有实验结果十分接近,表明该方法对低Z原子体系基组态能量的计算是可行的. 相似文献
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多体展开方法虽然已经广泛地用于估算弱相互作用体系的能量,但是其并不适用于计算共价团簇和金属团簇的能量. 本文提出了一种适用于计算共价体系能量的相互作用多体展开(IMBE)方法. 在相互作用多体展开方法中,体系的能量表示为孤立原子的能量及该原子与其他周围原子间相互作用的和. 首先将该方法应用于计算氮团簇的能量,且多体展开截断至四体项. 结果表明:与传统的多体展开方法相比,相互作用多体展开方法可以显著地降低能量误差. 另外,以密度泛函理论计算结果为参考,相互作用多体展开方法估算能量的误差不依赖于体系的大小和结构,说明相互作用多体展开方法比较适合用于估算共价相互作用大体系的能量. 相似文献
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《化学物理学报》2021,(6)
多体展开方法虽然已经广泛地用于估算弱相互作用体系的能量,但是其并不适用于计算共价团簇和金属团簇的能量.本文提出了一种适用于计算共价体系能量的相互作用多体展开(IMBE)方法.在相互作用多体展开方法中,体系的能量表示为孤立原子的能量及该原子与其他周围原子间相互作用的和.首先将该方法应用于计算氮团簇的能量,且多体展开截断至四体项.结果表明:与传统的多体展开方法相比,相互作用多体展开方法可以显著地降低能量误差.另外,以密度泛函理论计算结果为参考,相互作用多体展开方法估算能量的误差不依赖于体系的大小和结构,说明相互作用多体展开方法比较适合用于估算共价相互作用大体系的能量. 相似文献
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吴国祯 《原子与分子物理学报》1988,(1)
本文导出了多核体系中单电子能量的解析隐函数表示。运用这方法,对H_2~+分子的基态能量做了计算,结果是好的。此外,还对H(?)ckel模型的成键、非键和反键轨道的能量做了计算。本文所提示的方法对于计算和键长、健角有关的势垒课题将是方便的。 相似文献
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采用多组态相互作用方法及Rayleigh- Ritz变分法,计算了类铍O4+离子1s22s2p3Po态的非相对论能量,并详细分析了如何选择质量最好的变分波函数.运用截断变分方法进一步饱和函数空间得到能量的改进量,并考虑相对论修正、质量极化效应等获得了相对论能量计算值.计算结果表明,此理论计算方法可得到高精度的能量计算值. 相似文献
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利用基于密度泛函理论下的窗算符技术求解含时薛定谔方法计算了H原子在长脉冲强激光场中能量谱, 并与文献[8]中的动量空间的投影技术方法的计算结果进行了比较。在文献[8]给出的最大光电子能量范围内,我们的计算结果与文献[8]中的计算结果符合得很好,但是我们的计算结果能够给出比文献[8]中能量更高的光电子能谱,光电子能量谱的变化趋势也与实际的物理过程相符。同时我们也给出了最大光电子能量与激光强度关系的经验公式,利用我们的经验公式计算的最大光电子能量与经典计算预测的最大光电子能量符合得很好,这表明们的计算方法可靠,能够给出高精度的计算结果。因此利用基于密度泛函理论下的窗算符方法能很好地用来研究H原子在长脉冲强激光场中的阈上电离的性质。 相似文献
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H4体系的正方形结构及能量的计算 总被引:5,自引:5,他引:0
本文用通道耦合计算方法对H_4体系的正方形结构及能量进行计算和研究,得到了以正方形边长R为变量的能量曲线。结果表明,在R=2.16a_0处有极小能量-2.0701hartrees。 相似文献
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《Journal of luminescence》1987,37(6):287-291
The diffusion equation is numerically solved for the case of dipole-dipole energy transfer accompanied by material diffusion. The time-dependent second-order rate constant is computed for a whole range of time and diffusion coefficients. A discussion of the obtained results in comparison with approximate analytical solutions of the problems is given. 相似文献
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The Reflection of Magneto-Thermoelastic $P$ and $SV$ Waves at a Solid Half Space Using Dual-Phase-Lag Model
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Ahmed E. Abouelregal 《advances in applied mathematics and mechanics.》2011,3(6):745-758
The dual-phase-lag heat transfer model is employed to study the reflection
phenomena of $P$ and $SV$ waves from a surface of a semi-infinite
magneto-thermoelastic solid. The ratios of reflection coefficients to that
of incident coefficients are obtained for $P$- and $SV$-wave cases. The
results for partition of the energy for various values of the angle of
incidence are computed numerically under the stress-free and rigidly fixed
thermally insulated boundaries. The reflection coefficients are depending on
the angle of incidence, magnetic field, phase lags and other material
constants. Results show that the sum of energy ratios is unity at the
interface. The results are discussed and depicted graphically. 相似文献
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ABSTRACTIn this study, a computational examination of the electronic transitions and through-space energy transfer processes lends insight into the experimental electronic spectra of a redox-sensitive rhodamine–anthraquinone dyad. Electronic transitions were calculated using density functional theory (DFT) and time-dependent DFT (TDDFT) based on models optimised from single-crystal X-ray diffraction (XRD) ion positions. DFT calculations were performed on gas-phase models using the Vienna Ab Initio Software Package (VASP) with the functional developed by Perdew, Burke, and Ernzerhof (PBE) on a basis set of plane waves. Using the DFT results, select transitions were evaluated based on a dipole–dipole coupling mechanism to find the Förster resonance energy transfer coupling, the square of which is approximately proportional to the rate of energy transfer between the donor and the acceptor. Electronic transitions during the relaxation of charge carriers are also investigated using nonadiabatic molecular dynamics. In order to investigate the transitions contributing to key peaks in the experimental absorbance spectra, TDDFT calculations were performed in Gaussian 09 with the B3LYP functional on the sensor in solution phase, which is simulated using a polarisable continuum model (PCM). The computed electron transfer process from the excited rhodamine to the quinone correlates better with the experimental data than does the computed Förster resonance energy transfer (FRET) process. This computed electron transfer process is faster than the radiative lifetime of the fluorescent state, which collectively suggests that the charge transfer process quenches fluorescence. These results support the observation that fluorescence is more prominent in the oxidised sensor than in the reduced sensor. 相似文献
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本文讨论α粒子在聚变堆中的分布。将α粒子分为高能的和热化的两部分,并引用慢化密度概念,得到了α粒子分布函数所满足的慢化-扩散方程组。对于典型的托卡马克聚变堆参数,在简化的条件下解析地求解了方程组,得到了α粒子的分布和自加热率。最后,比较了用不同扩散系数的计算结果。
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Oriol Guasch 《Journal of sound and vibration》2011,330(25):6223-6236
An experimental statistical energy analysis method is proposed that requires neither input power measurements nor strong restrictive hypothesis on the nature of coupling between subsystems. Coupling loss factors are obtained from direct or blocked energy transmissibilities provided that total or internal loss factors are known, for instance, from application of the energy decay rate method. In turn, direct transmissibilities are computed from standard measurable energy transmissibilities, following the ideas of the direct transfer approach to transmission path analysis. The theoretical background of the proposed formulation is presented together with a numerical example to indicate how it could be applied in a practical case. 相似文献
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Xuan Hoang Khoa Le Hakan F. Oztop Fatih Selimefendigil Mikhail A. Sheremet 《Entropy (Basel, Switzerland)》2022,24(4)
Heat transport augmentation in closed chambers can be achieved using nanofluids and extended heat transfer surfaces. This research is devoted to the computational analysis of natural convection energy transport and entropy emission within a closed region, with isothermal vertical borders and a heat-conducting solid fin placed on the hot border. Horizontal walls were assumed to be adiabatic. Control relations written using non-primitive variables with experimentally based correlations for nanofluid properties were computed by the finite difference technique. The impacts of the fin size, fin position, and nanoadditive concentration on energy transfer performance and entropy production were studied. It was found that location of the long fin near the bottom wall allowed for the intensification of convective heat transfer within the chamber. Moreover, this position was characterized by high entropy generation. Therefore, the minimization of the entropy generation can define the optimal location of the heat-conducting fin using the obtained results. An addition of nanoparticles reduced the heat transfer strength and minimized the entropy generation. 相似文献