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921.
Raman and infrared spectra of calcurmolite were recorded and interpreted from the uranium and molybdenum polyhedra, water molecules and hydroxyls point of view. U O bond lengths in uranyl and Mo O bond lengths in MoO6 octahedra were calculated and O H…O bond lengths were inferred from the spectra. The mineral calcurmolite is characterised by bands assigned to the vibrations of the UO2 units. These units provide intense Raman bands at 930, 900 and 868 and 823 cm−1. These bands are attributed to the anti‐symmetric and symmetric stretching modes of the UO2 units, respectively. Raman bands at 794, 700, 644, 378 and 354 cm−1 are attributed to vibrations of the MoO4 units. The bands at 693 and 668 cm−1 are assigned to the anti‐symmetric and symmetric Ag modes of the terminal MO2 units. Similar bands are observed at 797 and 773 cm−1 for koechlinite and 798 and 775 cm−1 for lindgrenite. It is probable that some of the bands in the low wavenumber region are attributable to the bending modes of MO2 units. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
922.
Hua-Gen Yu 《Journal of Molecular Spectroscopy》2009,256(2):287-298
An exact variational algorithm is presented for calculating vibrational energy levels of pentaatomic molecules without any dynamical approximation. The quantum mechanical Hamiltonian of the system is expressed in a set of orthogonal coordinates defined by four scattering vectors in the body-fixed frame. The eigenvalue problem is solved using a two-layer Lanczos iterative diagonalization method in a mixed grid/basis set. A direct product potential-optimized discrete variable representation (PO-DVR) basis is used for the radial coordinates while a non-direct product finite basis representation (FBR) is employed for the angular variables. The two-layer Lanczos method requires only the actions of the Hamiltonian operator on the Lanczos vectors, where the potential-vector products are accomplished via a pseudo-spectral transform technique. By using Jacobi, Radau and orthogonal satellite vectors, we have proposed 21 types of orthogonal coordinate systems so that the algorithm is capable of describing most five-atom systems with small and/or large amplitude vibrational motions. Finally, an universal program (PetroVib) has been developed. Its applications to the molecules , and the van der Waals cluster He3Cl2 are also discussed. 相似文献
923.
We have studied the adsorption, vibration, and diffusion of N atoms on Ru(0 0 0 1), , and surfaces by means of the 5-parameter Morse potential (5-MP) of interaction between atomic nitrogen and a metal surface. The adsorption sites, adsorption geometry, binding energy and eigenvibration of atomic nitrogen on the different ruthenium surfaces are calculated. It is shown that atomic nitrogen always preferably occupies the high coordination sites on Ru surfaces. The 4-fold site is the preferable adsorption site for atomic nitrogen on both open and surfaces while 3-fold site is the most stable adsorption site for atomic nitrogen on both Ru(0 0 0 1) and surfaces. Moreover, we find the lowest energy pathway of diffusion and diffusion barriers of atomic nitrogen on the surfaces. 相似文献
924.
Jong Won Kim Sangkeun Son Gil Soo Kim Junnosuke Otaka Yuzuki Miura Atsuya Muranaka Masanobu Uchiyama Jung-Sook Lee Mina Jang Sung-Kyun Ko Shunji Takahashi Hiroyuki Osada Jae-Hyuk Jang Jong Seog Ahn 《Tetrahedron letters》2019,60(45):151227
LC/MS-based chemical screening of fungal extract fraction library led to identification of three 2,3-aryl substituted furanone metabolites (1–3), including one known butenolide glycoside (1) whose stereochemistry remained unsolved and two new compounds gotjawaside and gotjawalide (2 and 3), from Auxarthron sp. KCB15F070, a fungus isolated from a soil sample of the volcanic island Jeju, Korea. Their planar structures were elucidated by 1D- and 2D-NMR spectroscopic and HRESIMS spectrometric techniques, and the absolute configurations of three compounds were solved using a combination of chemical derivatizations and computational analysis of vibrational circular dichroism (VCD) spectra. 相似文献
925.
采用从头算的多参考组态相互作用(MRCI)方法并结合基组aug-cc-pCVQZ计算了CO分子基态(X1Σ+)的势能曲线和偶极矩曲线,得到的势能曲线、偶极矩曲线分别与RKR势、文献的偶极矩曲线吻合较好。利用所得的势能,求解双原子分子核运动的Schrdinger方程找到了CO分子X1Σ+态转动量子数J=0时的70个振动态,对于每一振动态,分别计算了其振动能级G(v)、转动惯性常数Bv和离心畸变常数Dv,并把计算结果与已知的42个实验值做了详细比较,结果表明,计算的振动能级G(v)、转动惯性常数Bv、离心畸变常数Dv与实验值符合较好。利用G(v),Bv导出的光谱常数[谐振频率ωe(2 160.1 cm-1)、非谐振频率ωeχe(13.1 cm-1)、转动常数Be(1.918 cm-1)、振转耦合常数αe(0.017 3 cm-1)]也与实验值的光谱常数[ωe(2 169.8 cm-1),ωeχe(13.3 cm-1),Be(1.931 cm-1),αe(0.017 5 cm-1)]较为符合,这在一定程度上证明了方法MRCI/Aug-cc-pCVQZ对CO分子基态性质的计算是合适而可靠的。利用乘积近似方法计算了CO分子在常温、中温、高温时的配分函数,在此基础上,计算了CO分子在T=296 K时的1-0跃迁带的谱线强度,通过比较发现,计算所得的线强度与HITRAN数据库符合较好。进一步计算的CO分子X1Σ+态1-0,2-0,3-0,4-0,2-1,3-1和4-1跃迁带的带强度也与实验值较为吻合,同时首次计算了CO分子X1Σ+态3-2跃迁带、4-2跃迁带的线强度及带强度。 相似文献
926.
927.
基于二苯基乙二酮结构优化,在TD-B3LYP/6-31+G*水平上讨论了两个异构体在气相和液相中的吸收和发射光谱.溶液中的计算采用可极化连续介质模型.结果表明,溶剂极性增加更有利于顺式非平面构型的形成,两个异构体的T1和S1态以及顺式非平面结构的S2态都源于双羰基上的n→π*. 相似文献
928.
高浓度NaBF4/DMF溶液中的离子溶剂化和离子缔合 总被引:2,自引:1,他引:1
利用振动光谱技术和量子化学方法研究了NaBF4/DMF溶液中的离子缔合和离子溶剂化现象。DMF分子的谱带变化表明,Na^ 与DMF分子的相互作用是通过DMF分子羰基上的氧原子进行的。Na^ 的溶剂化层内含有4个DMF分子,呈近似的四面体结构。而BF4^-谱带的变化表明,溶液中存在着离子缔合,有直接接触离子对生成。直接接触离子对的含量随溶液浓度增加而增大。 相似文献
929.
930.
Unraveling Vibrational Wavepacket Dynamics using Femtosecond Ion Yield Spectroscopy and Photoelectron Imaging
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Bing Zhang 《化学物理学报(中文版)》2019,32(1):35-45
Time-resolved photoionization is a powerful experimental approach to unravel the excited state dynamics in isolated polyatomic molecules. Depending on species of the collected signals, different methods can be performed: time-resolved ion yield spectroscopy (TR-IYS) and time-resolved photoelectron imaging (TR-PEI). In this review, the essential concepts linking photoionization measurement with electronic structure are presented, together with several important breakthroughs in experimentally distinguishing the oscillating wavepacket motion between different geometries. We illustrate how femtosecond TR-IYS and TR-PEI are employed to visualize the evolution of a coherent vibrational wavepacket on the excited state surface. 相似文献