Intramolecular vibrational redistribution and vibrational predissociation in 9-cyanoanthracene-Ar van der waals complexes

Processes of intramolecular vibrational redistribution and vibrational predissociation in 9-cyanoanthracene—Ar van der Waals complexes are investigated; their effect on the probabilities of nonradiative transitions is establsihed. Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 2, pp. 184–191, March–April, 1998.     

经典Lucas-Fibonacci数列的上、下界公式研究

本文在研究van der Waerden数的过程中,在把van der Waerden数的问题转化成关于线性不等式组解数问题的基础上,发现局部不等式组的解数S_p与经典Lucas- Fibonacci序列有关,同时在此基础上给出了经典Lucas-Fibonacci序列S_p的一个上、下界公式.     

Unusual features of the dispersion force in layered and striated nanostructures

A discussion is presented on some physics behind the unusually long ranged dispersion forces recently predicted between one-dimensional and nanolayered structures with a zero electronic energy gap, such as metallic nanotubes and graphitic structures. The various results for these systems, previously obtained via a variety of formalisms, are here re-derived systematically from a single approach.     

Molecular theory of phase equilibria in model and real associated mixtures III. Binary solutions of inert gases and n-alkanes in ammonia and methanol

Using new molecular models of ammonia and methanol and thermodynamic perturbation theory, the global phase diagrams of model mixtures of these compounds with a van der Waals fluid, representing a simple nonpolar fluid, have been calculated. The global phase diagram of these mixtures is much richer than that of corresponding aqueous mixtures. More types of critical line behavior are found, including the presence of van Laar points and a small region where the mixtures exhibit a closed liquid-liquid immiscibility loop (Type VI phase behavior). The individual mixture components are characterized by two molecular parameters, which can be adjusted to their critical temperature and critical volume; the mixture model itself contains no adjustable parameters. It is shown that the theory gives qualitatively correct predietions of mixtures with n-alkanes. This includes the prediction of Type III critical line behavior for small and large values of the ratio of the critical temperatures of the components, and Type II over a large range of conditions, including the presence or absence of absolute or limited azeotropy, and temperature and pressure extrema of critical lines and their dependence on the number of carbon atoms.     

麦克斯韦等面积法则在范氏气体中的应用

对与范德瓦耳斯气体状态方程有关的几个问题作了进一步分析,给出了一种证明麦克斯韦等面积法则的方法,并指出了有关文献的不妥之处.     

Period-doubling bifurcation in an extended van der Pol system with bounded random parameter

An extended van der Pol system with bounded random parameter subjected to harmonic excitation is investigated by Chebyshev polynomial approximation. Firstly the stochastic extended van der Pol system is reduced into its equivalent deterministic one, solvable by suitable numerical methods. Then we explored nonlinear dynamical behavior about period-doubling bifurcation in stochastic system. Numerical simulations show that similar to the conventional period-doubling phenomenon in deterministic extended van der Pol system, stochastic period-doubling bifurcation may also occur in the stochastic extended van der Pol system. Besides, different from the deterministic case, in addition to the conventional bifurcation parameters, i.e. the amplitude and frequency of harmonic excitation, in the stochastic case the intensity of random parameter should also be taken as a new bifurcation parameter.     

Influence of the chain length of long molecules on the equation of state in binary gas-liquid mixtures

The simple Flory-Huggins model can be combined with the lattice gas as was done by Tompa and others. Here the same method is used to obtain the van der Waals equation of state for a binary gas-liquid system containing a solute consisting of segmented molecules. The simplified equation of state developed here is useful for the study of the critical properties of such systems, in particular, the dependence of the various parameters on the chain length of the molecules.     

The crystal and molecular structure of N-(17-methoxy-phenyl)-2-chloropyrrolo (2,3- b ) quinoline

N-(17-methoxy-phenyl)-2-chloropyrrolo (2,3-b) quinoline was solved by direct methods and refined to anR of 0.104 for 950 observed reflections. The intensity data were collected by the multiple film equi-inclination Weissenberg technique and estimated visually. The packing of the molecule is stabilised by van der Waals interaction. The pyrrolo (2,3-b) quinoline ring system is planar and the methoxy phenyl ring is approximately perpendicular to the plane of this ring system with a dihedral angle of 86.5°.     

In search of the Griffiths shield region

The van der Waals equation of state for binary mixtures has been used to determine the location and shape of the Griffiths shield region (where three tricritical lines intersect). If one takes the geometric mean fora ₁₂, the arithmetic mean forb ₁₂, and the configurational free energy as ideal, the center of the Griffiths shield region is found only when the ratio of molecular sizes is infinite. When the Flory equation for the configurational free energy for mixtures of chain molecules is substituted for the ideal form, the results appear to be somewhat different. However, for all the cases studied, with systems which approach geometric mean behavior one finds the shield region only when the ratio of molecular size is very large and when the internal pressure of the small molecule is very much greater than that of the long-chain molecule.This paper is dedicated to our colleague Howard Reiss on the occasion of his 66th birthday.     

Structure of interfaces from uniformity of the chemical potential

It is shown that a generalized chemical potential suggested by the potential-distribution theory is uniform even in a nonuniform fluid. Leng, Rowlinson, and Thompson had already observed its uniformity through the liquid-vapor interface in the penetrable-sphere model, in mean-field approximation. Following those authors, we exploit the uniformity of that generalized chemical potential to obtain unified and transparent derivations of the results of Ono and Kondo and of van der Waals on the liquid-vapor interfaces in the lattice-gas model and in the model of attracting hard spheres, respectively, both in mean-field approximation.Work supported by the National Science Foundation and the Cornell University Materials Science Center.