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991.
大气臭氧层因吸收太阳紫外光, 是人类必不可少的保护伞. 氟利昂在太阳光辐射下解离生成破坏臭氧的游离态氯原子, 是破坏大气臭氧层的主要元凶之一. 本文利用飞行时间质谱技术和离子速度成像技术研究了氟利昂F113(三氟三氯乙烷)分子在800 nm 飞秒光作用下的多光子电离解离动力学. 利用飞行时间质谱探测技术, 得到了三氟三氯乙烷在该波长飞秒激光作用下发生多光子电离解离产生的碎片质谱. 通过荷质比对碎片质谱进行了详细的标定和分析. 在质谱上未发现母体离子, 所有观察到的离子都是由于激光脉冲作用下产生的碎片. 三个最主要的碎片离子是CFCl2+, CF2Cl+, C2F3Cl2+. 通过飞行时间质谱标定, 发现并归属了多个解离通道. 三个主要的解离机理分别为: 1) C-Cl键断裂直接生产氯自由基的通道C2F3Cl3+→C2F3Cl2++Cl; 2) C--C键断裂C2F3Cl3+→CFCl2++CF2Cl; 3) C--C键断裂C2F3Cl3+→CF2Cl++CFCl2. 利用离子速度成像技术对这三个主要通道产生的碎片离子进行成像, 得到了C2F3Cl2+, CFCl2+和CF2Cl+离子的速度影像. 由C--Cl键断裂产生的碎片离子C2F3Cl2^{+}的速度分布由两个高斯分布曲线拟合, 而由C--C键断裂产生的碎片离子CFCl2+和CF2Cl+可以用一个高斯曲线拟合. 通过影像分析得到了解离碎片的平动能分布和角向分布各向异性参数等详尽的动力学信息. 结合高精度密度泛函理论计算对解离动力学进行了进一步的分析和讨论.深入认识氟利昂的解离动力学可为进一步控制破坏臭氧层提供理论参考和实验依据. 相似文献
992.
A. L. Vikharev A. M. Gorbachev M. A. Lobaev A. B. Muchnikov D. B. Radishev V. A. Isaev V. V. Chernov S. A. Bogdanov M. N. Drozdov J. E. Butler 《固体物理学:研究快报》2016,10(4):324-327
We report on building a novel chemical vapor deposition (CVD) reactor for diamond delta‐doping. The main features of our reactor are: a) the use of rapid gas switching system, (b) the reactor design providing the laminar gas flow. These features provide the creation of ultra‐sharp interfaces between doped and undoped material and minimize the prolonged ”tails” formation in the doping profile. It is proved by optical emission spectroscopy that gas switching time is not more than 10 seconds. Using the novel reactor we have grown the nanometer‐thin layers of boron doped diamond. The FWHM of boron concentration profile is about 2 nm which is proved by SIMS. It is shown that the both single delta‐layer and multiple delta‐layers could be grown using the novel CVD reactor. In principle, the reactor could be used for diamond delta doping with other dopants, like nitrogen, phosphorus etc. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
993.
为了避免机载光电吊舱中共口径光学系统内部由于道威棱镜旋转引起的激光照射脉冲偏振态的变化,利用琼斯矩阵对道威棱镜的偏振特性与四分之一波片、半波片补偿道威棱镜旋转引起的激光脉冲偏振态变化进行了理论分析和实验验证。结果表明:线偏振的激光脉冲通过旋转一定角度的道威棱镜时,激光脉冲偏振态变为椭圆偏振,偏振态发生变化;而激光脉冲首先通过旋转一定角度的四分之一波片与半波片时,可使通过道威棱镜系统的激光脉冲偏振态保持不变,且两波片旋转角度与道威棱镜旋转角度之间存在一种非线性关系。采用偏振补偿方法可有效避免机载共口径光学系统中道威棱镜引起的激光脉冲偏振态变化,提高激光脉冲能量利用率,降低激光脉冲后向散射抑制难度。 相似文献
994.
We analyze a coherent injection of single electrons on top of the Fermi sea in two situations, at finite-temperature and in the presence of pure dephasing. Both finite-temperature and pure dephasing change the property of the injected quantum states from pure to mixed. However, we show that the temperature-induced mixedness does not alter the coherence properties of these single-electron states. In particular two such mixed states exhibit perfect antibunching while colliding at an electronic wave splitter. This is in striking difference with the dephasing-induced mixedness which suppresses antibunching. On the contrary, a single-particle shot noise is suppressed at finite temperatures but is not affected by pure dephasing. This work therefore extends the investigation of the coherence properties of single-electron states to the case of mixed states and clarifies the difference between different types of mixedness. 相似文献
995.
We analyze a coherent injection of single electrons on top of the Fermi sea in two situations, at finite-temperature and in the presence of pure dephasing. Both finite-temperature and pure dephasing change the property of the injected quantum states from pure to mixed. However, we show that the temperature-induced mixedness does not alter the coherence properties of these single-electron states. In particular two such mixed states exhibit perfect antibunching while colliding at an electronic wave splitter. This is in striking difference with the dephasing-induced mixedness which suppresses antibunching. On the contrary, a single-particle shot noise is suppressed at finite temperatures but is not affected by pure dephasing. This work therefore extends the investigation of the coherence properties of single-electron states to the case of mixed states and clarifies the difference between different types of mixedness. 相似文献
996.
997.
D. Vignolles A. Audouard V. N. Laukhin J. Béard E. Canadell N. G. Spitsina E. B. Yagubskii 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(4):383-388
The oscillatory magnetoresistance spectrum of the
organic metal (BEDO)5Ni(CN)4. 3C2H4(OH)2 has
been studied up to 50 T, in the temperature range from 1.5 K to
4.2 K. In high magnetic field, its Fermi surface corresponds to a
linear chain of quasi-two-dimensional orbits coupled by magnetic
breakdown (MB). The scattering rate consistently deduced from the
data relevant to the basic α and the MB-induced β
orbits is very large which points to a significant reduction of
the chemical potential oscillation. Despite of this feature, the
oscillations spectrum exhibits many frequency combinations. Their
effective masses and (or) Dingle temperature are not in agreement
with either the predictions of the quantum interference model or
the semiclassical model of Falicov and Stachowiak. 相似文献
998.
《印度化学会志》2021,98(9):100114
We demonstrate how a back-propagation artificial neural network can be trained to represent a potential energy surface (PES) in a formless manner with limited data points and exploited to predict interaction energies for configurations not included in the training set. A similar exercise is undertaken for predicting the eigenvalues and eigenvectors of a model Hamiltonian matrix that delicately depends on parameters and exhibits crossing of eigen values. 相似文献
999.
1000.
Guohai Deng Dr. Sudip Pan Dr. Jiaye Jin Prof. Dr. Guanjun Wang Prof. Lili Zhao Prof. Dr. Mingfei Zhou Prof. Gernot Frenking 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(1):412-418
Two structural isomers containing five second-row element atoms with 24 valence electrons were generated and identified by matrix-isolation IR spectroscopy and quantum chemical calculations. The OCBNO complex, which is produced by the reaction of boron atoms with mixtures of carbon monoxide and nitric oxide in solid neon, rearranges to the more stable OBNCO isomer on UV excitation. Bonding analysis indicates that the OCBNO complex is best described by the bonding interactions between a triplet-state boron cation with an electron configuration of (2s)0(2pσ)0(2pπ)2 and the CO/NO− ligands in the triplet state forming two degenerate electron-sharing π bonds and two ligand-to-boron dative σ bonds. 相似文献