共查询到20条相似文献,搜索用时 41 毫秒
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XUZhao-Xin ZHANGJun YINGHe-Ping 《理论物理通讯》2003,40(5):623-630
The ground-state and thermodynamic properties of quantum mixed-spin chains of 1/2-1/2-1-1 and 3/2-3/2-1-1 are investigated by a quantum Monte Carlo simulation with the loop-cluster algorithm. For 1/2-1/2-1-1 chain, we find it hastwo phases separated by an energy-gap vanishing point in the ground-state. For 3/2-3/2-1-1 chain,the numerical results show two energy-gap vanishing points isolated by different phases in its ground-state. Our calculations indicate that all these ground state phases can be understood by means of valence-bond-solid picture, and the thermodynamic behavior at finite temperatures is continuous as a function of parameter α=J2/J1. 相似文献
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The ground-state and thermodynamic properties of quantum mixed-spin chains of1/2-1/2-1-1and 3/2-3/2-1-1are investigated by a quantum Monte Carlo simulation with the loop-cluster algorithm. For 1/2-1/2-1-1 chain, we find it has two phases separated by an energy-gap vanishing point in the ground-state. For 3/2-3/2-1-1 chain, the numerical results show two energy-gap vanishing points isolated by different phases in its ground-state. Our calculations indicate that all these ground state phases can be understood by means of valence-bond-solid picture, and the thermodynamic behavior at finite temperatures is continuous as a function of parameterα=J2/J1. 相似文献
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《Radiophysics and Quantum Electronics》2000,43(12):999-1002
Radiophysics and Quantum Electronics - 相似文献
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《Radiophysics and Quantum Electronics》2000,43(12):1003-1010
Radiophysics and Quantum Electronics - 相似文献
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Olivier Mathieu 《Communications in Mathematical Physics》1996,176(2):467-474
Letn be an integer. Denote byA
n one of the following two graded vector spaces: (a) the space of all multilinear Poisson polynomials of degreen (with a grading described below), or (b) the cohomology of the space of alln-uples of complex numbersz
1,..., zn withz
izj forij. We prove that the natural action of
n
on each homogeneous component ofA
n can be extented to an hidden
n+1
-action and we compute the corresponding character (the
n
-character being already given by Klyaschko and Lehrer-Solomon formulas). 相似文献
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Eric Séré 《Communications in Mathematical Physics》1995,172(2):293-316
Consider a smooth Hamiltonian system in 2N
,
, the energy surface ={x/H(x)=H(0)} being compact, and 0 being a hyperbolic equilibrium. We assume, moreover, that {0} is of restricted contact type. These conditions are symplectically invariant. By a variational method, we prove the existence of an orbit homoclinic, i.e. non-constant and doubly asymptotic, to 0. 相似文献
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In polar and nonpolar solvents, tetrahydroisoquinoline emits S2 (ππ1) → S0 and S1 (ππ1) → S0 dual fluorescence and T1 (ππ1) → S0 phosphorescence on S2 (ππ1) ← S0 excitation. When excited by S1 (ππ1) ← S0 the molecule yields S1 (ππ1) → S0 fluorescence and T1 (ππ1) → S0 phosphorescence in nonpolar solvent but only fluorescence in polar solvents. Probable participation of intermediate S1 (nπ1), T1(nπ1) states in intersystem crossing and internal conversion processes and its significance in interpreting the results are discussed. 相似文献
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The FT-IR, FT-Raman and FT-NMR spectra of the compound 4-(4-Chlorophenyl)-1H-imidazole (4-ClPI) was recorded and analyzed. Density functional method has been used to compute optimized geometry, vibrational wavenumbers and NMR spectra of the 4-ClPI. Only one tautomeric form was found most stable by using B3LYP functional with the 6?C311++G(d,p) as basis sets. The detailed interpretation of the vibrational spectra was carried out with the aid of total energy distribution (TED) following the scaled quantum mechanical force field methodology. 相似文献
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S.P. McGlynn 《Journal of Molecular Spectroscopy》1974,49(2):214-225
The absorption and emission spectra of 1- and 2-naphthoic acids and a number of their derivatives have been investigated. The S1, T1, and S0 energy levels of solvent H-bonded monomers and internally H-bonded dimers are affected by the type of H-bonding, by periinteractions, by steric factors provided by substituent groups, and by solvent effects. The excimer fluorescence of 1-naphthoic acid has been detected and is the sole fluorescece of the crystal; it is attributed to a tetrameric sandwich complex of two dimers. The 1-naphthoic acid crystal also exhibits delayed excimer flurescence of a triplet-triplet annihilative type. 相似文献
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Y. Erdogdu D. Manimaran M. T. Güllüoǧlu M. Amalanathan I. Hubert Joe S̨. Yurdakul 《Optics and Spectroscopy》2013,114(4):525-536
The FT-IR, FT-Raman and FT-NMR spectra of the compound 4-(4-Fluoro-phenyl)-1H-imidazole (4-FPI) were recorded and analyzed. Density functional method (B3LYP level with the 6–311G(d, p) and 6–311++G(d, p) and cc-pVQZ as basis sets) has been used to compute optimized geometry, vibrational wavenumbers of the 4-FPI. Only one tautomeric form was found most stable by using DFT/B3LYP. The detailed interpretation of the vibrational spectra was carried out with the aid of total energy distribution following the scaled quantum mechanical force field methodology. Potential Energy Surface scan studies has also been carried out by ab initio calculations with the same basis sets. 相似文献
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The use of fluorescent solid films of a 1-(p-butyloxyphenyl)-4-(p-cyanophenyl)buta-1E, 3E-diene as an efficient temperature sensor is described. The fluorescence changes in these films are proposed to occur due
to a reversible temperature-dependent variation in its monomer-aggregate ratio. Photoisomerization of the butadiene chromophore
in solid films was observed to occur only at elevated temperatures (> 120∘C), making the material also useful for reversible photochemical generation of fluorescence patterns with nondestructive readout
properties. 相似文献
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