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采用密度泛函B3LYP和组态相互作用方法在6-311++G**水平上计算了甲烷从基 态到前六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B 0n( n=1—6).同时研究了外电场对甲烷分子的激发态的影响规律.结果表明,随外电场强度增大 ,系统总能量变化较小,同时最高占据轨道HOMO与最低空轨道LUMO的能隙gaps变小,费米能 级Fermi levels略有下降.甲烷基态(X~lAl)在外场作用下,易 于向高激发态产生跃迁.
关键词:
4')" href="#">CH4
激发态
外电场 相似文献
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减光子压缩真空态的反群聚效应 总被引:4,自引:2,他引:2
利用玻色产生算符的逆算符及玻色湮没算符作用于压缩真空态来构造减光子压缩真空态,并通过计算减光子压缩真空态的二阶关联函数来讨论它们的光子反群聚性质。数值计算结果表明,在两种情况下所得到的减光子压缩真空态当湮没光子数k为奇数时均呈现出群聚效应,而当k为偶数时呈现反群聚效应。所呈现的反群聚效应对应的压缩参量η的取值区间与湮没的光子数k有关,在玻色产生箅符的逆算符的作用下随着k的增加,反群聚效应对应的压缩参量η的取值区间扩大,在玻色湮没算符作用下则相反。同时,作出二阶关联函数随压缩参量η变化的曲线来描述减光子压缩真空态所呈现的反群聚效应的变化特性。 相似文献
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研究q-玻色湮没算符高次幂(k≥3)的正交归一本征态的数学结构,在此基础上讨论了它们的数学性质及其q-压缩和振幅N次方压缩特性.发现它们能组成一个完备的希尔伯特(Hilbert)空间;且当k为偶数时,这些本征态均可存在振幅N次方压缩. 相似文献
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提出无磨损界面摩擦微观能量耗散机理的复合振子模型,指出滑动摩擦过程同时存在整体做低频弹性振动的宏观振子和界面原子受激励产生热振动的微观振子,并在此基础上分析了宏观振子和微观振子对摩擦能量耗散的不同影响. 通过对界面原子的动力学分析,指出摩擦过程界面激励力的频率是能量转换的关键:在平衡力作用阶段,界面作用力的频率趋于零,因而可以直接作用到每个原子,力的作用效果是整体和均匀的;在失稳跳跃阶段,由于界面激励力的频率极高,造成摩擦界面原子获得的能量分布很不均匀,从而产生不可逆的能量耗散过程. 与目前通用的独立振子模型比较,复合振子模型能够更准确描述摩擦能量耗散过程,可为摩擦控制提供理论指导.
关键词:
摩擦
能量耗散机理
复合振子模型
独立振子模型 相似文献
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SiH2 radicals were generated in a free jet by the 193 nm photolysis of phenylsilane and the LIF excitation spectra of vibrationally excited SiH2 (
) were observed. The spectra were utilized to determine the vibrational frequencies and anharmonic constants for the symmetric stretching and the bending vibrations. Analysis of the Fermi resonance between the (100) and (020) levels gave interaction energy of 12.4 cm−1. 相似文献
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Raman spectra of the uranyl titanate mineral betafite were obtained and related to the mineral structure. A comparison is made with the spectra of uranyl oxyhydroxide hydrates. Observed bands are attributed to the (UO2)2+ stretching and bending vibrations, U–OH bending vibrations and H2O and (OH)? stretching, bending and libration modes. U–O bond lengths in uranyls and O?H···O bond lengths are calculated from the wavenumbers assigned to the stretching vibrations. Raman bands of betafite are comparable with those of the uranyl oxyhydroxides. The mineral betafite is metamict as is evidenced by the intensity of the UO stretching and bending modes being of lower intensity than expected and by bands that are significantly broader. 相似文献
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Raman spectra of the uranyl titanate mineral brannerite were analysed and related to the mineral structure. A comparison is made with the Raman spectra of uranyl oxyhydroxide hydrates. The observed bands are attributed to the TiO and (UO2)2+ stretching and bending vibrations, U OH bending vibrations, as well as H2O and (OH)− stretching, bending and libration modes. U O bond lengths in uranyls and O H···O bond lengths were calculated from the wavenumbers assigned to the stretching vibrations. Raman bands of brannerite are in harmony with those of the uranyl oxyhydroxides. The mineral brannerite is metamict, as is evidenced by the intensity of the UO stretching and bending modes being of lower intensity than expected and with bands that are significantly broader. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Joseph Grondin Jean‐Claude Lassgues Dominique Cavagnat Thierry Buffeteau Patrik Johansson Roman Holomb 《Journal of Raman spectroscopy : JRS》2011,42(4):733-743
Imidazolium‐based ionic liquids (ILs) involving anions of variable coordinating strength have been investigated using infrared (IR) and Raman spectroscopies, density functional theory (DFT) calculations and selective deuteration of the imidazolium CH groups. Particular emphasis has been placed on the vibrational assignments of the anion and cation internal vibrations, a prerequisite before any interpretation of spectral changes due to ion–ion interactions in these unconventional liquids. The vibrations of highly symmetric and weakly coordinating anions, such as PF6−, have unperturbed wavenumbers, but unexpected IR or Raman activity for some modes, showing that the anion is subjected to an anisotropic electric field. The stretching as well as the in‐plane and out‐of‐plane bending modes of the imidazolium CH groups are anharmonic. They give broad bands that reflect a large distribution of interactions with the surrounding anions. All the bending modes are mixed with ring vibrations and the stretching modes are complicated by Fermi resonance interactions with overtones and combination of in‐plane ring modes. However, the stretching vibration of the quasi‐diatomic C(2) D bond appears to be a good spectroscopic probe of the increasing cation–anion interactions when the coordinating strength of the anion increases. The broad absorption observed in the far IR with weakly coordinating anions remains practically unchanged when the acidic C(2) H imidazolium bond is methylated and even when the imidazolium cation is substituted by tetra‐alkyl ammonium or pyrrolidinium cations. It is concluded that this absorption is a general feature of any IL, coming from the relative translational and librational motions of the ions without needing to invoke C(2) H anion hydrogen bonds. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Raman and infrared spectra of five uranyl oxyhydroxide hydrates, becquerelite, billietite, curite, schoepite and vandendriesscheite, are reported. The observed bands are attributed to the (UO2)2+ stretching and bending vibrations, U OH bending vibrations and H2O and (OH)− stretching, bending and libration modes. The U O bond lengths in uranyls and the O H···O bond lengths are calculated from the wavenumbers assigned to the stretching vibrations. They are close to the values inferred and/or predicted from the X‐ray single‐crystal structure. The complex hydrogen‐bonding network arrangement was proved in the structures of all the minerals studied. This hydrogen bonding contributes to the stability of these uranyl minerals. Copyright © 2006 John Wiley & Sons, Ltd. John Wiley & Sons, Ltd. 相似文献
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Ray L. Frost Silmarilly Bahfenne Jií ejka Jií Sejkora Jakub Plil Sara J. Palmer 《Journal of Raman spectroscopy : JRS》2010,41(7):814-819
The kaolinite‐like phyllosilicate minerals bismutoferrite BiFe3+2Si2O8(OH) and chapmanite SbFe3+2Si2O8(OH) have been studied by Raman spectroscopy and complemented with infrared spectra. Tentatively interpreted spectra were related to their molecular structure. The antisymmetric and symmetric stretching vibrations of the Si O Si bridges, δ SiOSi and δ OSiO bending vibrations, ν (Si Oterminal)− stretching vibrations, ν OH stretching vibrations of hydroxyl ions, and δ OH bending vibrations were attributed to the observed bands. Infrared bands in the range 3289–3470 cm−1 and Raman bands in the range 1590–1667 cm−1 were assigned to adsorbed water. O H···O hydrogen‐bond lengths were calculated from the Raman and infrared spectra. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Jan Loun Jií ejka Jií Sejkora Jakub Plil Milan Novk Ray L. Frost Sara J. Palmer Eloise C. Keeffe 《Journal of Raman spectroscopy : JRS》2011,42(7):1596-1600
The Raman spectrum of bukovskýite [Fe3+2(OH)(SO4)(AsO4)· 7H2O] has been studied and compared with that of an amorphous gel containing specifically Fe, As and S, which is understood to be an intermediate product in the formation of bukovskýite. The observed bands are assigned to the stretching and bending vibrations of (SO4)2− and (AsO4)3− units, stretching and bending vibrations and vibrational modes of hydrogen‐bonded water molecules, stretching and bending vibrations of hydrogen‐bonded (OH)− ions and Fe3+ (O,OH) units. The approximate range of O H···O hydrogen bond lengths was inferred from the Raman spectra. Raman spectra of crystalline bukovskýite and of the amorphous gel differ in that the bukovskýite spectrum is more complex, the observed bands are sharp and the degenerate bands of (SO4)2− and (AsO4)3− are split and more intense. Lower wavenumbers of δ H2O bending vibrations in the spectrum of the amorphous gel may indicate the presence of weaker hydrogen bonds compared to those in bukovskýite. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Aq-deformed boson-realization model is presented to study both stretching and bending vibrations of sulfur dioxide, where Fermi
resonances are taken into account. Our results are compared with those of other models. 相似文献
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Ray L. Frost 《辐射效应与固体损伤》2013,168(1):24-29
Raman spectra of the uranyl titanate mineral holfertite Ca x U2?x Ti(O8?x OH4x )·3H2O were analyzed and related to the mineral structure. Observed bands are attributed to the TiO and (UO2)2+ stretching and bending vibrations, U–OH bending vibrations, and H2O stretching and bending. The mineral holfertite is metamict, as is evidenced by the order/disorder of the mineral. Unexpectedly, the Raman spectrum of holfertite does not show any metamictization. The intensities of the UO stretching and bending modes show normal intensity and the bands are sharp. 相似文献