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1.
E Krishnakumar 《Pramana》1998,50(6):591-606
The development and the first results from an experiment to carry out dissociative attachment to excited molecules are discussed. A brief summary of the relevance and status of such measurements are given. Apart from measuring the absolute cross sections from excited and state selected SO2 molecule, we have been able to characterize the negative ion resonances using the excited state dissociative attachment. In addition, the state specificity of the electron attachment process has been used to derive information on the excited neutral state itself which has not been possible using optical spectroscopy. The applicability of this technique to other species are also discussed.  相似文献   

2.
A relativistic self-consistent Dirac-Slater model has been used in a study of the electronic structure of 5d-metal hexafluorides. Experimental absorption spectra have been compared with calculated energies obtained as one-electron energy differences. The calculated “crystal field” splitting between the relativistic analog oft 2g ande g levels, as well as spinorbit splitting of thet 2g level, has been found to be in good agreement with experimental data. Ionization energies which agree well with available spectra have been calculated using a transition state procedure. From a Mulliken population analysis of the molecular levels and ground state charge densities the validity of the classical crystal-field model is discussed.  相似文献   

3.
Electron-hole pairing due to the Coulomb interaction in the system of two graphene sheets has been considered. The critical transition temperature has been determined as a function of both the distance between the electron and hole Fermi lines and the triangular distortion of their spectrum. It has been shown that when the distance between Fermi lines is longer than a critical value, the temperature of the transition to a state with nonzero momentum of Cooper pairs (Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state) is higher than the temperature of the transition to the Bardeen-Cooper-Schrieffer state. The Josephson effect for the FFLO state has been analyzed, which is due to the tunneling of charge carriers between the graphene sheets. It has been shown that the spatial structure of the order parameter of the system in this state can be reconstructed, i.e., the FFLO state can be identified from the dependence of the tunneling current on the magnetic field parallel to the graphene sheets. Other experimental methods for studying the phase diagram of the system have been discussed.  相似文献   

4.
A possibility of breaking spatial homogeneity of vacuum as a result of interaction of a quark with a Bose field has been investigated. It is shown that there can be in a ground state of the wave-packet type. The energetic conditions for such a state have been found. The origin of deep inelastic processes and the phenomenon of quark confinement are discussed.  相似文献   

5.
An intramolecular excited charge transfer (CT) analysis of imidazole derivatives has been made. The determined electronic transition dipole moments has been used to estimate the electronic coupling interactions between the excited charge transfer singlet state (1CT) and the ground state (S0) or the locally excited state (1LE). The properties of excited 1CT state imidazole derivatives have been exploited by the significant contribution of the electronic coupling interactions. The excited state intramolecular proton transfer (ESIPT) analysis has also been discussed.  相似文献   

6.
The exchange coupling energy for two magnetized monolayers embedded symmetrically in a metal and polarized in an arbitrary direction has been investigated in contact interaction approximation. Since the model can be solved exactly in particular for free-electron case, the coupling energy contributed from both extended state electrons and bound state electrons is calculated rigorously. For weak interaction, it is found that the leading term in the power-series expansion of density of states can give a correct coupling energy compared with rigorous one while extended state electrons give a much larger coupling energy. Furthermore, the relevant problems such as phase shift, 90°coupling and lattice effects have been discussed; an asymptotic expression of the interlayer coupling has been derived in a different way and used to calculate the exchange energy between magnetic layers in copper with Fermi surface obtained from de Haas-van Alphen effect.  相似文献   

7.
The effect of positional substitution of amino group on the ground and excited state dipole moments of quinoline ring has been investigated using solvatochromic shift methods. The excited state dipole moments of 5aminoquinoline (5AQ) and 3aminoquinoline (3AQ) have been estimated from the spectral data in different non-polar, polar aprotic and polar protic solvents using Bakhshiev and Kawski-Chamma-Viallet equations. It has been observed that both grounds as well as excited state dipole moments for 5AQ are higher than those for 3AQ by approximately a factor of two. Higher values of the excited state dipole moments for both 3AQ and 5AQ as compared to corresponding ground state values have been attributed to intramolecular charge transfer processes. The role of specific solute-solvent interaction on excited state dipole moment in addition to the general solvent effects has been discussed.  相似文献   

8.
Experimental potential energy curves have been constructed for the molecule Cu65 Cl35 by the Rydberg-Klein-Rees-Vanderslice method. Perturbations in the B'πstate have been predicted due to the C'πstate and large interactions have been observed in the D'π state which have been discussed. The dissociation energy for the Cu65 Cl35 molecule has been estimated (2.5ev) by a relation derived from Lippincott three parameter potential function.  相似文献   

9.
The first CH stretching overtone band system of diacetylene (1,3-butadiyne) in the range of 6350–6750 cm?1 has been recorded with a high resolution Fourier transform infrared interferometer at room temperature. Although the spectrum obtained may be resolved rotationally, two different computational procedures have been used to enhance the resolution due to severe congestion in the central parts of the band system. It has become possible both to find one new band and to achieve higher precision. Altogether five bands with the lower state being the ground vibrational state have been analysed rotationally. The results obtained are discussed in the context of a previous molecular beam study of a small part of the same band system.  相似文献   

10.
The current status of developments in the field of ferroelectric memory devices has been considered. The rapidly growing market of non-volatile memory devices has been analyzed, and the current state of the art and prospects for the scaling of parameters of non-volatile memory devices of different types have been considered. The basic constructive and technological solutions in the field of the design of ferroelectric memory devices, as well as the ??roadmaps?? of the development of this technology, have been discussed.  相似文献   

11.
制冷空调系统替代工质的发展现状及方向   总被引:3,自引:0,他引:3  
张超  王坤 《低温与超导》2005,33(4):69-72
本文主要针对CFC11、CFC12以及HCFC22介绍了目前替代工质的发展现状,阐述了混合工质以及氨、二氧化碳、碳氢化合物等自然工质作为替代工质的特点以及其发展现状,总结了制冷空调系统替代工质的发展方向。  相似文献   

12.
The γ-spectrum, emitted in the β-γ-decay of the 5+ state of In 116, has been measured with a Ge(Li)-detector. 19 unknown transitions in Sn 116 have been found, most of which could be fitted uniquely into the established level scheme. A new β-transition (logft=5.6) to the 3,096 keV level has been found. Branching ratios are given and a possible band structure in Sn 116 is discussed.  相似文献   

13.
于淥 《物理学报》1965,21(1):75-91
本文利用广义正则变换和自洽场方法,讨论了单个杂质对超导体的影响。证明在磁性杂质附近,可能形成一个束缚态的元激发,其能量位于能隙之中。求出了能级和波函数的解析表达式,并计算了束缚能级所引起的附加电磁吸收。讨论了与此有关的隧道和高频吸收实验。此外,还讨论了非磁性杂质对连续谱元激发的影响及杂质附近能隙的变化。  相似文献   

14.
本文用Wigner特征函数方法将压缩的概念推广到一般量子态;详细讨论了一类新的光场状态——压缩的混沌态的量子统计性质,并提出辐射场与其共轭场的光子配组的概念作为其压缩性质的物理解释.  相似文献   

15.
The time evolution of a squeezed coherent state conditioned by the results of a single and double heterodyne measurement is discussed. The mean values of quadratures as well as the dynamics of quadrature uncertainties have been obtained within the framework of the theory of continuous measurements based on filtration equations. It has been found that while the mean values depend on the measured noise, the uncertainties in the optical quadratures are deterministic. Explicit solutions for the latter have been provided. Finally, a time development of the squeeze parameter for the posterior squeezed coherent state has been found.  相似文献   

16.
The properties of polariton Raman spectra for the internal vibration region of NH4Cl crystal are discussed. These spectra have been recorded by means of a copper laser ( λ = 5105 and 5782A?) for sample temperature T=80 and 10°K.According to the theory a polariton singularities in the region of a polar bound state has been obtained. The two-particle bands have been studied and a very complicate structure inside of these bands has been revealed. Moreover, multiphonon singularities at polariton curves have been observed. The experimental polariton law has been compared to the theory and a conclusion has been made as to the necessity of a further development of the theory.  相似文献   

17.
A B-spline-type basis set method for the calculation of hydrogen atom in strong magnetic fields in the frame of spheroidal coordinates has been introduced. High accurate energy levels of hydrogen in the magnetic field, with strength ranging from 0 to 1000 a.u., have been obtained. For the ground state, 1s0, energies with at least 11 significant digits have been obtained. For the low-lying excited state, 2p−1, energies with at least 9 significant digits are obtained. The method has also been applied to the calculation of hydrogen Rydberg states in laboratory magnetic fields. Energy spectra with at least 10 significant digits are presented. A comparison with other results in the literatures has been performed. Our results are comparable to the most accurate one up to date. A possible extension to the cases of parallel and crossed electric and magnetic fields have been discussed.  相似文献   

18.
For one even-A rotational nucleus (152Sm) a semi-classical third order perturbation treatment of Coulomb excitation with a hexadecapolo interaction included has been carried out considering bombarding conditions which have formerly been found to be suitable for an experimental determination of certainE4 transition moments. Numerical values of the most important contributions to the perturbation hierarchy are given and the present state of quantal corrections is discussed.  相似文献   

19.
The deformation properties of several isotopes of the elements Os, Pt and Hg have been computed by means of Hartree-Fock plus BCS calculations. The Hartree-Fock potential has been derived from the Skyrme interaction SIII. Two approximations have been used for the treatment of pairing correlations: the constant (versus deformation) gap method and the constant (versus deformation) pairing matrix element method. A good agreement with experimental data is obtained for ground state deformation properties except for the exact location of the prolate-oblate transition as a function of the neutron number. For one nucleus 184Hg, the pairing matrix elements have been calculated from the Gogny interaction D1, in order to study their single-particle state — and deformation — dependence. From these results, the validity of the two approximations used for pairing correlations is discussed.  相似文献   

20.
A new model Hamiltonian has been developed to study the vibration-inversion-rotation energy levels of ammonia. In this model the inversion motion is removed from the vibrational problem by allowing the molecular reference configuration to be a function of the large amplitude motion coordinate. The treatment follows closely that developed by Hougen, Bunker, and Johns for the study of triatomic molecules.The numerical methods that have been used to solve the zeroth-order Hamiltonian describing the inversion-rotation energy levels of NH3 and ND3 in the ground vibrational state are discussed. Certain group-theoretical problems concerning the symmetry classification of the states of ammonia are also discussed.  相似文献   

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