共查询到17条相似文献,搜索用时 62 毫秒
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HBr分子的爱因斯坦自发辐射系数的计算 总被引:1,自引:0,他引:1
本文从第一性原理出发,计算了HBr分子v≤7,J≤14,Δv=1,R,P支谱线的爱因斯坦自发辐射系数A^v‘J’v^nJ^n。测量了HBr红外发射的振转谱线强度,证实由理论计算获得的A^vJ’V^nJ^n系数是可靠的。 相似文献
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介绍了一种研究双原子分子势能函数的新方法 -能量自洽法的建立、它的物理思想、它的部分应用成果 相似文献
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曙光一号自由电子激光自发辐射放大的理论计算 总被引:1,自引:0,他引:1
曙光一号自由电子激光装置用自发辐射放大(ASE)机理,在毫米波波段测得了数百毫瓦的光信号输出。利用三维WAGFEL程序,结合曙光一号直线感应加速器型自由电子激光放大器参数,详细地分析了自发辐射放大的增益、输出功率随电子束的质量(包括束流能散度、流强、发射度等因素)的变化情况,给出了相应的定标关系;并且考察了摇摆场随机误差对自发辐射放大功率的影响。最后对自发辐射放大的实验结果进行了分析。 相似文献
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考虑真空涨落能量为负的特点,提出一个能够简洁描述原子与真空涨落相互作用的方程,得到原子处于激发态的概率随时间变化的关系,讨论了原子自发辐射的速率与真空涨落的强度的关系. 相似文献
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采用理论计算与动高压实验相结合的方法,提出了一个计算剪切模量温度系数G′T的新方法.首先用理论方法计算一个中间数据G(PS),然后再与动高压实验数据G(PH)结合在一起计算出G′T,并针对93钨合金材料进行了计算.计算结果表明剪切模量温度系数G′T开始是随温度和压力变化的,但在高温高压下,它趋近于一常数.对于93钨合金,这个常数约为-004GPa/℃.同时,这也是对Steinberg本构模型中的剪切模量温度系数为常数的一个证明.并且,当把这一常数代入剪切模量温度系数的计算式中,将重新计算出的剪切模量与实验测得的剪切模量结果进行了比较,结果表明二者符合得很好,从而证明了本计算的剪切模量温度系数的正确性.
关键词:
有限应变物态方程
剪切模量温度系数
Steinberg本构模型
动高压实验 相似文献
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Theoretical study of the structure and analytic potential energy function for the ground state of the PO2 molecule 下载免费PDF全文
In this paper, the energy, equilibrium geometry, and harmonic frequency of the ground electronic state of PO2 are computed using the B3LYP, B3P86, CCSD(T), and QCISD(T) methods in conjunction with the 6-311++G(3df, 3pd) and cc-pVTZ basis sets. A comparison between the computational results and the experimental values indicates that the B3P86/6-311++G(3df, 3pd) method can give better energy calculation results for the PO2 molecule. It is shown that the ground state of the PO2 molecule has C2v symmetry and its ground electronic state is X2A1. The equilibrium parameters of the structure are Rp-o = 0.1465 am, ZOPO = 134.96°, and the dissociation energy is Ed = 19.218 eV. The bent vibrational frequency Ul = 386 cm-1, symmetric stretching frequency v2 = 1095 cm-1, and asymmetric stretching frequency ua = 1333 em-1 are obtained. On the basis of atomic and molecular reaction statics, a reasonable dissociation limit for the ground state of the PO2 molecule is determined. Then the analytic potential energy function of the PO2 molecule is derived using many-body expansion theory. The potential curves correctly reproduce the configurations and the dissociation energy for the PO2 molecule. 相似文献
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Spontaneous emission behavior from atoms (or molecules) in one-dimensional photonic crystal with a defect is investigated. Taken all the TE and TM modes into account, the normalized spontaneous emission rate of the atom is calculated as a function of the position of the atom in the crystal. Results for both nonabsorbing dielectric structure and absorbing dielectric structure are presented. With the increase of the thickness of the defect in which the atoms are embedded, the oscillations of the spontaneous emission rate versus the position of the atom become dense and the lifetime distribution becomes narrow and sharp. The PC effect may lead to the coexistence of both accelerated and inhibited decay processes. 相似文献
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AlH分子结构与分析势能函数 总被引:1,自引:4,他引:1
本文运用群论及原子分子反应静力学方法,推导了 AlH分子的基态(X1Σ+)、第一激发态(A1Π)及第三激发态(C1S+)的电子态及相应的离解极限.并使用SAC/SAC-CI方法,采用D95 (d)、6-311g(d)和cc-PVTZ等基组对AlH分子的基态(X1Σ+)、第一激发态(A1Π)和第三激发态(C1S+)的平衡结构和谐振频率进行了几何优化计算.通过对三个基组的计算结果与实验结果的比较,得到cc-PVTZ基组是三个基组中最优基组的结论.使用cc-PVTZ基组,对AlH 分子的基态(X1Σ+)、第一激发态(A1Π)和第三激发态(C1S+)进行了单点能扫描计算,并给出了AlH的基态(X1Σ+)、第一激发态(A1Π) 和第三激发态(C1S+)的Murrell-Sorbie函数形式的电子态的完整势能函数,进而得到了AlH分子第一激发态(A1Π)的激发能较小的结论. 相似文献
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We study the coherent control of spontaneous emission in a driven three-level atomic system. In particular we consider the quantum interference effects including energy shifts due to the counter-rotating terms. We show that the quantum interference resulting from the energy shifts has great influence on the evolution of the atomic population and the spontaneous emission spectrum. This makes it feasible to observe the effect of the counter-rotating terms in the long time limit. 相似文献
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Hong-Dong Zhao Mei Sun Li-Ying Han Ping He Hong-Li Tian 《Optical and Quantum Electronics》2007,39(15):1273-1280
The control of spontaneous emission is one of important characteristics of a planar microcavity. The integrals in the spherical
coordinate for TE and TM modes spontaneous emission spectra of a quantum well (QW) embedded in a planar microcavity are derived
with new variables dependent on wavelength and Taylor series including the two polarizations of the vacuum field. The approximate
expressions of spontaneous emission in QW planar microcavities are obtained. The approximate results show that spontaneous
emission spectra agree well with that in the numerical integral for planar semiconductor microcavities, in which Fermi-Dirac
distribution functions of electrons and holes are considered. The main contribution to the spontaneous emission, radiated
into all direction, has been found. 相似文献
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Ronggang Liu 《Optik》2014
We study the spontaneous emission spectrum of a five-level M-type atom driven by a microwave field, in which two upper levels are coupled by the same-coupled cavity waveguide reservoir to a lower level. The spectrum behavior presents a strong non-Lorentzian shape that originates from effective quantum interference in Markovian reservoir, in which the spectral line can be significantly enhanced and eliminated by adjusting the proper parameters of the system. However, for non-Markovian reservoir, it seems that the shape of emission spectrum is quite dependent on the geometry behavior of a coupled cavity waveguide. 相似文献
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The spontaneous emission properties of radio-frequency(RF)-driven multilevel atomic systems with three different configurations are investigated in details. It is demonstrated that, due to the presence of the RF-induced coherence in the multilevel system, a few interesting phenomena such as spectral-line narrowing, spectral-line enhancement, spectral-line suppression, and fluorescence-quenching can be realized under realistic experimental conditions. By inspecting single-RF-driven, double-RF-driven, and triple-RF-driven atomic systems, we find that (i) when only one RF-driven field is applied, there are two fluorescence-quenching points and four spectral lines; (ii) in the case of applying two RF-driven fields, there are three fluorescence-quenching points and five spectral lines; (iii) when applying three RF-driven fields, there are four fluorescence-quenching points and six spectral lines; and (iv) as expected, when the atomic system coupled by N RF-driven fields, there will be N + 1 fluorescence-quenching points and N + 3 spectral lines. Interestingly enough, the spectral-line enhancement, the spectral-line suppression, and the selective cancellation of fluorescence-quenching can be well controlled just by appropriately modulating the intensities and frequencies of the applied RF fields, respectively. The proposed schemes can be achieved by use of RF-driven fields into hyperfine levels in rubidium atomic systems. These investigations may find applications in high-precision spectroscopy. 相似文献