共查询到20条相似文献,搜索用时 78 毫秒
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黑索金(环三亚甲基三硝胺, RDX, C3H6O6N6)是一种非常重要的次级炸药, 因其高能量密度及对外界刺激的低感度而具有广泛的军事和工业应用. 为了能在生产、运输、存储以及使用中对其行为进行有效控制, 人们对它的化学性质、力学性质, 尤其是起爆进行了大量的研究. 炸药的起爆是一个非常复杂的过程, 其中最主要的问题之一就是能量是如何从连续介质尺度的刺激转移到原子尺度引起吸热分解的. 根据冲击波致爆的非平衡态Zel'dovich-von Neumann-Doering模型, 声子作为最初的热载体在整个过程中起着非常重要的作用. 实验上, 非弹性中子散射技术是研究晶体中原子和分子运动动力学的有力手段, 尤其是对于包含了大部分声子晶格模式的低频区域来说极具优势. 利用非弹性中子散射技术测得了RDX 在10–104 cm-1 范围内的振动谱, 结合固态量子化学计算, 对所测的12个振动模式进行指认. 研究结果有助于人们对起爆详细机理的认识. 相似文献
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Mode coupling in a protein molecule was studied by a molecular dynamics simulation of the intramolecular vibrational energy transfer in myoglobin at near zero temperature. It was found that the vibrational energy is transferred from a given normal mode to a very few number of selective normal modes. These modes are selected by the relation between their frequencies, like Fermi resonance, governed by the third order mode coupling term. It was also confirmed that the coupling coefficients had high correlation with how much the coupled modes geometrically overlapped with each other. 相似文献
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研究了粗糙金属银表面对分子间能量转移效应的影响,实验观察到吸附分子增强的敏化荧光,结合表面局域电磁理论分析表明,吸附于银表面的分子间非辐射能量转移率被增强10^2倍,证实了表面增强的分子间能量转移效应的存在。 相似文献
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Per Jensen 《Molecular physics》2013,111(17):1253-1285
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几种硝基苯类炸药在外电场作用下的分子特性 总被引:2,自引:0,他引:2
采用密度泛函理论中的B3LYP方法,在6-31G*水平上研究了外电场对一些硝基苯类炸药分子的总能量、偶极矩、分子轨道能级和前线轨道能量差等分子特性的影响;考察了在外电场作用下分子前线轨道能量差与炸药的电火花感度之间的关系.结果表明,在外电场作用下分子总能量降低,偶极矩增大、前线轨道能量差减小;分子前线轨道能量差与炸药的电火花感度之间几乎线性相关,且外电场对这种线性相关性无明显影响. 相似文献
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Theory of Radiationless Energy Relaxation of a Large Number of Coupled Molecular Normal Vibrations On the base of a general relaxation theory recently developed by the authors the dissipation and transfer of energy in a system of a large number of coupled molecular vibrations are studied. Especially, vibrations of the same kind belonging to molecules localized at different space points of a dense medium are considered. For a short-range and a long-range interaction potential time-dependent generalized damping parameters are calculated, which give rise to non-exponential decay laws for the vibrational energy of the molecules. 相似文献
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Heroin, morphine and narcotine are very large molecules having 50, 40 and 53 atoms respectively. Moderately high resolution
photoacoustic (PA) spectra have been recorded in 9.6 μm and 10.6 μm regions of CO2 laser. It is very difficult to assign the modes of vibrations for PA bands by comparison with conventional low resolution
IR spectra. The ab initio quantum chemical calculations were used for determining the molecular geometries and normal mode frequencies of vibrations
of these molecules for assignments of PA spectra. 相似文献
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The problem of nonlinear radial pulsations and surface vibrations of a charged bubble placed in an ideal incompressible dielectric liquid is asymptotically solved up to the second order of smallness by the method of many scales. It is shown that, in the case of nonlinear vibrations, resonance energy exchange may take place not only between surface modes but also between the radial mode and a surface mode. A new type of instability (other than Rayleigh instability against the self-charge), instability against the excess vapor pressure in the bubble, is discovered. The new type of instability shows up as energy transfer from the centrosymmetric pulsation mode to all initially excited surface vibration modes simultaneously. 相似文献
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G. Hähner J. P. Toennies Ch. Wöll 《Applied Physics A: Materials Science & Processing》1990,51(3):208-215
A normal mode analysis of experimental data from helium atom scattering (HAS) and electron energy loss spectroscopy (EELS) for vibrations of CO molecules adsorbed in on-top and bridge sites on Ni(100) is presented, using a refined force-constant analysis. The similar case of CO adsorbed on Pt(111) is reinvestigated, revealing a misassignment of normal modes in previous work. Finally, available experimental data for CO on Pt(111) is used to construct a trial potential energy surface. 相似文献
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In this work we study the spectrum of vibrational modes in metal nanoparticles with a dielectric core. Vibrational modes are
excited by the rapid heating of the particle lattice that takes place after laser excitation, and can be monitored by means
of pump-probe spectroscopy as coherent oscillations of transient optical spectra. In nanoshells, the presence of two metal
surfaces results in a substantially different energy spectrum of acoustic vibrations than for solid particles. We calculated
the energy spectrum as well as the damping of nanoshell vibrational modes. The oscillator strength of the fundamental breathing
mode is larger than that in solid nanoparticles. At the same time, in very thin nanoshells, the fundamental mode is overdamped
due to instantaneous energy transfer to the surrounding medium.
PACS 78.67.-n; 78.67.Bf; 63.22.+m 相似文献
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V. G. Klimenko R. N. Nurmukhametov E. A. Gastilovich S. A. Lebedev 《Optics and Spectroscopy》2000,88(3):339-345
The infrared and Raman spectra of the octachlorodibenzo-p-dioxine molecule are measured and all normal vibrational modes of the molecule are calculated. Each vibrational mode was assigned to the vibrations of certain functional groups of atoms in the molecule, taking into account the local symmetry characteristics of the vibration mode. A correlation of vibrational modes by their shape was established in a series of molecules: dibenzo-p-dioxine, 2,3,7,8-tetrachlorodibenzo-p-dioxine, and OCDX. The influence of substituents on vibrational frequencies was also examined. 相似文献
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将振动态能量碰撞转移较成熟的长程力理论应用到大质量分子体系,采用准经典计算方法建立235UF6和238UF6同位素分子的碰撞理论;对235UF6和238UF6同位素间分子间v3振动能量近共振碰撞转移过程进行研究;得到共振函数随能量差、共振转移概率和共振转移速率随温度的变化,发现它们随温度的增大而减小,说明碰撞分子的平动会降低其共振转移概率和速率,为控制235UF6和238UF6同位素分子间振动-振动转移引起的选择性损失这个激光光化学法分离铀同位素的关键问题提供理论依据,为实际分离铀同位素提供参考. 相似文献
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We introduce a machine learning model to predict atomization energies of a diverse set of organic molecules, based on nuclear charges and atomic positions only. The problem of solving the molecular Schr?dinger equation is mapped onto a nonlinear statistical regression problem of reduced complexity. Regression models are trained on and compared to atomization energies computed with hybrid density-functional theory. Cross validation over more than seven thousand organic molecules yields a mean absolute error of ~10 kcal/mol. Applicability is demonstrated for the prediction of molecular atomization potential energy curves. 相似文献
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Saturable Absorption Enchantment of Au Nanorods Based on Energy Transfer between Longitudinal and Transverse Energy Levels 下载免费PDF全文
Four kinds of Au nanorods(NRs)with different aspect ratios are designed to adjust the relationship between resonance energy level of longitudinal(L)and transverse(T)modes.During the femto-second Z-scan experiments,huge saturable absorption phenomena are observed while the energy level T is located between one to two times of the energylevel L.This means that the energy may transfer between longitudinal and transverse energylevels in the same and/or different Au NRs.It effectively depresses the production of revised saturated absorption and increases the saturable absorption efficiency.This method is significant for the preparation of high-efficiency saturable absorption devices. 相似文献