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1.
ABSTRACT

Based on ab initio calculations, our research group has built an analytical ground-state potential energy surface (PES) for hydrogen peroxide– noble gas (Ng) interactions, such as H2O2–He, H2O2–Ne, H2O2–Ar, H2O2–Kr, and H2O2–Xe complexes. From this PES, it was verified that the Ng presence does not affect the equilibrium values of the H2O2 dihedral angles. This happens because the H2O2 intramolecular barriers have much higher energies than the atom–bond interaction within these complexes. From this point of view, it is indeed reasonable to consider the H2O2 system as a rigid rotor, frozen at its equilibrium configuration. We present in this work the torsional motion for the H2O2 isolated system, the vibration–rotation energy levels and spectroscopic constants for hydrogen peroxide–noble gas by using the aforementioned PES. The predicted H2O2 torsional motions are in good agreement with both theoretical and experimental results available in the literature. Regarding H2O2–Ng ro-vibrational energies and spectroscopic constants, it is the first time that these calculations are presented in the literature. The current theoretical predictions are expected to be useful in the future experimental investigations.  相似文献   

2.
采用二项式方案构建了FenOm+(n+m=4)团簇的大量可能初始结构.运用广义梯度近似(GGA)密度泛函理论中的PW91交换关联泛函对这些初始结构进行优化和频率分析,得到12个稳定的异构体.在此基础上计算和分析了它们的结合能、对称性、键长、磁矩,最高占据轨道与最低未占据轨道的能隙.发现Fe—O键在FenOm+(n+m=4)团簇的稳定中具有重要作用,团簇的总磁矩主要取决于铁原子的磁矩和各个原子磁矩排布情况.  相似文献   

3.
Abstract

The electron spin resonance of γ-irradiated single crystals of methoxycarbonylcholine picrate hemihydrate, C7H16NO3 + · C6H2N3O7 ? · ½ H2O has been observed and analyzed for different orientations of the crystal in the magnetic field. The crystals have been investigated between 70 and 350 K. The spectra were found to be temperature independent and the radiation damage centers are attributed to – ?[Obar]OCH3 and –CH2CH2O? radicals. The g and hyperfine coupling constants were found to be almost isotropic with an average, g = 2.0060, a H1 = 4.4G for –CH2CH2O?, g = 2.0050, a H2 = 3.5G for –CH2CH2O? and g = 2.0045, a H = 3.5 G for –?[Obar]OCH3. These values indicate a long-range coupling between the unpaired electron and H protons.  相似文献   

4.
CCSD(T) and MP2 results using the aug-cc-pV5Z basis set are reported for chain, cyclic and other structures of the clusters (H2)n, n?=?2-8, (CO2)n, n?=?2-6 and (HF)n, n?=?2-8. In chain-like structures of (H2)n and (CO2)n, with the bonding type of the dimer maintained, the dissociation energy De of the dimer doubles for the trimer, triples for the tetramer, and so on. Due to these systems being dominated by short-range forces, interactions are essentially restricted to neighbouring monomers. For other types of (H2)n and (CO2)n structures, the multipliers relative to the dimerisation energy can be much higher. Dissociation energies for the hexamers in S6 symmetry of both H2 (379?cm?1) and CO2 (4925?cm?1) are over ten times the respective dimerisation energies. For the chain-like trimer of HF, however, De is in excess of double the dimer value. Mainly due to longer-range dipolar forces, the interactions reach beyond the neighbouring monomers. The interaction energy between HF monomers in chains follows an approximate R?2 (R being the F–F distance) relationship, The calculated dissociation energies of the HF octamer are 15,985?cm?1 (factor of 10.4) for the chain, and 21,003?cm?1 (factor of 13.7) for the C6h cyclic structure.  相似文献   

5.
6.
刘艳  任维义  王阿署  刘松红 《物理学报》2008,57(3):1599-1607
鉴于K2分子电子态的振动能谱和分子离解能De在实际研究和应用中的重要性,应用Sun,Ren等人提出的基于微扰理论的代数方法(AM)和基于AM的代数能量方法(AEM)研究了K2分子的X1Σ+g,a3Σ+u,0-g,B1Πu< 关键词: 2分子')" href="#">K2分子 代数方法 高阶振动能级 离解能  相似文献   

7.
Previous investigations have shown that it is difficult to acquire the infrared (IR) spectra of M+(H2O) (M?=?Cu, Au) using a single IR photon by attaching an Ar atom to M+(H2O). To explore whether the IR spectra can be obtained using the two Ar atoms tagging method, the geometrical structures, IR spectra and interaction energies are investigated in detail by ab initio electronic structure calculations for M+(H2O)Ar2 (M?=?Cu, Au) complexes. Two conceivable isomeric structures are found, which result from different binding sites for two Ar atoms. CCSD(T) calculations predict that two Ar atoms are most likely to attach to Cu+ for the Cu+(H2O)Ar2 complex, while the Au+(H2O)Ar2 complex prefers the isomer in which one Ar atom attaches to an H atom of the H2O molecule and the other one is bound to Au+. Moreover, the calculated binding energies of the second Ar atom are smaller than the IR photon energy, and so it is possible to obtain the IR spectra for both Cu and Au species. The changes in the spectra caused by the attachment of Ar atoms to M+(H2O) are discussed.  相似文献   

8.
The structural, electronic and magnetic properties of small gallium clusters doped with Cobalt have been studied using spin-polarised density functional theory. The binding energy per atom, second-order differences of total energies and fragmentation energies of equilibrium geometries of the host Gan+1 and doped GanCo (n = 1–12) clusters are computed. Doped clusters are found to be more stable than pure Ga clusters; Ga3Co, Ga5Co and Ga8Co clusters are exceptionally stable. Doping with Co changes the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO–LUMO) gap, and also affects the magnetic moments of clusters.  相似文献   

9.
10.
An experimental study has been performed shedding light on the conformational energies of the asymmetric ether n-butyl ethyl ether. Rotational spectroscopy between 7.8 GHz and 16.2 GHz has identified two conformers of n-butyl ethyl ether, C4H9OC2H5. In these experiments spectra were observed as the target compound participated in an argon expansion from high to low pressure causing molecular rotational temperatures to be below 4 K. For one conformer, 95 pure rotational transitions have been recorded, for the second conformer, 20 pure rotational transitions were recorded. Rotational constants and centrifugal distortion constants are presented for both butyl ethyl ether conformers. The structures of both conformers have been identified by exploring the multi-dimensional molecular potential energy surface using ab initio calculations. From the numerous low energy conformers identified using ab initio methods, the three lowest conformers were pursued at increasingly higher levels of theory, i.e. complete basis set extrapolations, coupled cluster methods, and also taking into consideration zero point vibrational energies. The two conformers observed experimentally are only revealed to be the two lowest energy conformers when high levels of quantum chemical methodologies are employed.  相似文献   

11.
唐春梅  朱卫华  邓开明 《中国物理 B》2010,19(11):114202-114202
This paper uses the density functional theory to analyse the stabilities,bond characters,static linear polarisabilities,and aromaticities of the ’in-out’ isomerism H n-60 @C n H 60 (n=70,72,74).The binding energies,C-H bond energies,and energy gaps explore that the ’in-out’ isometric perhydrogenation of C n (n=70,72,74) can remarkably improve the stabilities.The static linear polarisabilies of H n-60 @C n H 60 (n=70,72,74) are indeed relative to their shapes,while they show almost nonaromatic character.This study can suggest that the ’in-out’ isometric perhydrogenation of fullerenes could lead to the invention of entirely novel potential hydrogen storage nanomaterials.  相似文献   

12.
Qun Wei  Qi-Ming Xu 《Pramana》2009,72(4):735-742
By taking into account slight interactions, i.e. spin-spin, spin-other-orbit and orbit-orbit interactions, in addition to spin-orbit interaction, the zero-field splitting of 4 T 2 state for 3d3 ions at tetragonal symmetry has been studied. The convergence of the approximation perturbation formula of 4 T 2 state for 3d3 ions at tetragonal symmetry has been investigated, and the contributions to zero-field splitting arising from magnetic interaction and tetragonal crystal field are discussed. It is found that there exists combined mechanism between magnetic interactions and tetragonal crystal field.   相似文献   

13.
The archetypical and phaseless vacuum magnetic flux density of O(3) electrodynamics, the B (3) field, is derived from the irreducible representation of the Einstein group and is shown to be accompanied by a vacuum energy density which depends directly on the square of the scalar curvature R of curved spacetime. The B (3) field and the vacuum energy density are obtained respectively from the non-Abelian part of the field tensor F and the non-Abelian part of the metrical field equation. Both of these terms are given by Sachs [5].  相似文献   

14.
The structures, stabilities and electronic properties of neutral and anionic B3Sin (n?=?1–17) clusters have been systemically investigated on the basis of density functional theory at the B3LYP/6-311?+?G(d) level and CALYPSO structure prediction method. The structural searches show that three boron atoms tend to form B3 triangle encapsulated into Sin cages with the increasing number of silicon atoms. Most of the lowest energy structures can be derived by using the squashed pentagonal bipyramid structure of B3Si4 and B3Si4? as the major building unit. The relative stabilities are studied based on the calculated binding energies, second-order difference of energies and HOMO–LUMO gaps of the lowest energy structures. In addition, Hirshfeld, natural population analysis, Bader approaches and natural electronic configuration are performed to explore the charge transfer. At last, molecular orbital, magnetic properties, IR, Raman and UV–vis spectra are also, respectively, analysed for providing strong support for essential theoretical and experimental research.  相似文献   

15.
运用单双取代二次组态相关(QCISD)方法,在6-311++G(3df,3pd)基组水平上,对BeH2和H2S分子的结构进行了优化计算,得到基态BeH2分子的稳定结构为Dh构型,电子态为X1Σ+g,平衡核间距RBeH=0.13268nm,R关键词: 2')" href="#">BeH2 2S')" href="#">H2S Murrell-Sorbie函数 多体项展式理论 解析势能函数  相似文献   

16.
In this work, the excited state intermolecular potential energy surface of the Ar–CS2(V1B2) van der Waals complex was evaluated for the first time. The calculation of more than 4000 single-point interaction energies for the complex using an equation-of-motion coupled-cluster model with single and double substitutions level of theory with extended basis set involving bond functions has been performed. After fitting the interaction energies to analytical functions, the emission spectra of the Ar–CS2(V1B2) complex related to the different stationary points on the potential energy surface were calculated. It was seen that the intensity and the position of the emission spectra are dependent on the orientation of the Ar atom around the bent excited CS2 and the distance between two components. The information about the structural parameters of the complex related to the global minimum was obtained under the pseudodiatomic approximation with assistance of ab initio potential. The presented investigation could be useful for further theoretical and experimental studies of Ar–CS2(V1B2) complex.  相似文献   

17.
罗文浪  阮文  张莉  谢安东  朱正和 《物理学报》2008,57(8):4833-4839
获得T2O(X1A1)解析势能函数的主要困难在于Born-Oppenheimer近似下T2O(X1A1)与H2O(X1A1)势能函数的不可区分性.然而,在Born-Oppenheimer近似下,分子势能函数实际上是键长、键角这些 关键词: 2O(X1A1)')" href="#">T2O(X1A1) 同位素效应 解析势能函数  相似文献   

18.
D P Ahalpara 《Pramana》1979,12(2):179-201
The low-lying collective bands of positive parity states in (fp) shell nuclei are described in the deformed Hartree-Fock method by projecting states of definite angular momenta from ‘the lowest energy intrinsic states in (sd)−1 (fp) n+1 configurations. The modified Kuo-Brown effective interaction for (fp) shell and modified surface delta interaction (MSDI) for a hole in (sd) shell with a particle in (fp) shell have been used. The collective bands of states are in general well reproduced by the effective interactions. The excitation energies of the band head states are however off by about one MeV. The calculated magnetic moments of the band headj=3/2+ states are in reasonable agreement with experiment. Using effective chargese p=1.33e ande n=0.64e we get fairly good agreement forE(2) transitions. The hinderedM(1) transition strengths are reproduced to the correct order however they are slightly higher compared to experiment.  相似文献   

19.
Magnetoelectric coupling in RMn2O5 (with R?=?non magnetic) multiferroics have been studied using the Monte Carlo simulation. The variation of magnetization and the polarization of RMn2O5 multiferroic have been determined. The system undergoes a magnetic transition at TN and a further reduction of the temperature leads to a ferroelectric transition at TC?<? TN depending on the coupling strength. Magnetic and ferroelectric hysteresis loops are obtained for several temperatures values. Variation of polarization with the external magnetic field of RMn2O5 has been given. Variation of polarization and magnetization with the electric field of RMn2O5 has been obtained.  相似文献   

20.
ABSTRACT

We present a theoretical study of the ground electronic state potential of the Ca+Ar2 complex and of its photoabsorption spectra, simulated at temperatures ranging between 20 and 220?K. These calculations exploit a Monte-Carlo (MC) method, based on a one-electron pseudo-potential approach. A pairwise additive potential fitted to coupled cluster ab initio points, is used to model the Ca+Ar2 complex. Our study shows that the most stable form of Ca+Ar2 is a bent C2v structure, whereas the linear isomer is located at around 90?±?10?cm?1 above in energy. The analysis of the photoabsorption spectra establishes that a structural transition from bent Ca+Ar2 to linear ArCa+Ar occurs at T~100?K. Trends in binding energies of both isomers, bond lengths and bond angles are also discussed. Molecular orbital overlaps provide an explanation for the order of stability between the bent and linear structures.  相似文献   

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