摘要:

The use of non-equilibrium statistical Green's functions for the derivation of kinetic equations is considered. Strong interactions are studied. A number of Boltzmann-like equations are derived for quantum, classical, Markovian and non-Markovian, inhomogeneous systems.

ISSN:0026-8976    

DOI:10.1080/00268977400101481

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A three-dimensional classical trajectory analysis is used to determine the reaction dynamics of the reaction F + D2(v, J) → DF(v′, J′) + D on an assumed London-Eyring-Polanyi-Sato (LEPS) potential energy surface. Monte Carlo procedures are used to start each collision trajectory. An analysis is presented of the dependences of the total reaction cross sections σrand specific reaction cross sections σ(v, J, v′, ER) on the relative translational energy and initial vibrational and rotational energy of the reagent molecule D2(v, J). Data are presented of the temperature dependences of (1) the vibrational, rotational and translational energy distributions of the reaction products and (2) the rate constants for formation of DF in specific vibrational and rotational states. The probability that direct reaction between atomic fluorine and molecular deuterium will lead to formation of DF in thev′= 0 state was found to be zero. The ratiok(v′= 4)/k(v′= 3) appears to be independent of temperature and has a value of 0·65, which is in excellent agreement with recent infra-red chemiluminescence experimental data. The ratiok(v′= 2)/k(v′= 3) has a slight temperature dependence and, at room temperature, has a value of 0·28. The ratiok(v′= 1)/k(v′= 3) was assumed independent of temperature and was assigned a value of 0·08. The results are compared with available experimental data and with previous theoretical studies.

ISSN:0026-8976    

DOI:10.1080/00268977400101491

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A method is described for the direct measurement of spin-lattice relaxation rates between the triplet spin sublevels of phosphorescent molecules. The method also yields the correct values (in the presence of spin-lattice relaxation) for the total sublevel decay rates and can be used in conjunction with standard optically detected magnetic resonance experiments to find correct values for relative populating rate constants, radiative rate constants and steady state populations of the triplet sublevels. The technique is applied herein to the study of indole and tryptophan molecules in several environments.

ISSN:0026-8976    

DOI:10.1080/00268977400101501

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

This paper reports the angular dependence of the electron resonance spectrum of a spin probe dissolved in a smectic A mesophase. The spectra were analysed to obtain the angular variation of the linewidth coefficients and hence the angular linewidth coefficients. These angular coefficients may be interpreted by employing a theory of spin relaxation based on the strong collision model for molecular reorientation. Such an analysis yields values for the correlation times for reorientation about the long and short axes of the spin probe as well as the magnitude of the solute order parameter[Pbar]4. The possibility of interpreting the angular linewidth coefficients in terms of a theory based on the diffusion model for molecular reorientation is also explored. Relatively straightforward expressions for these coefficients can only be obtained from the diffusion model when the orientational order is high, as it is in a smectic phase. The analysis of the angular linewidth coefficients then provides values for the components of the diffusion tensor parallel and perpendicular to the long axis of the spin probe. The large anisotropy in the diffusion tensor may be indicative of the unhindered molecular motion about the long axis.

ISSN:0026-8976    

DOI:10.1080/00268977400101511

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The anisotropy of the potential between two atoms, one at least of which hasJ> ½, can cause partial re-alignment of the electronic angular momentum vector (i.e.MJtransitions) during collision. Within the framework of the semi-classical approximation, a single parameter akin to the Massey parameter is found to determine whether a given system will exhibit strong or weak coupling of the electronic to the relative atomic angular momentum. The consequence of these two coupling schemes for the position of the rainbow, the quenching of glory undulations and the magnitude of the total cross section are discussed. Particular reference is made to the metastable3P2state of Hg and the inert gases where the fine structure splitting is much larger than the relevant part of the interatomic potential. In the case of Kr* and Xe* the rainbow and glory features are strongly dependent on the initialMJstate of the atom and the glory structure should be suppressed. In contrast, scattering from systems such as Hg*/Na or Hg*/Hg should take place under weak coupling conditions.

ISSN:0026-8976    

DOI:10.1080/00268977400101521

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Nous donnons des résultats concernant les spectres V.H. et H.H. de la lumière diffusée par la quinoléine pour diverses températures et divers vecteurs d'onde. La théorie hydrodynamique à deux variables de Romanov et Solovev rend compte convenablement des résultats.

ISSN:0026-8976    

DOI:10.1080/00268977400101531

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A 220 MHz1H spectrum cyclopentadiene monomer dissolved in a nematic phase has been obtained and analysed to yield a set of dipolar coupling constants and orientation parameters. Ratios of interproton distances have been calculated from the dipolar couplings, taking into account averaging over harmonic vibrations.

ISSN:0026-8976    

DOI:10.1080/00268977400101541

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A method is proposed for calculating differential and total reaction cross sections for three-dimensional (3D) scattering processes fromS-matrix elements computed for planar (2D) systems. By approximating each 3DS-matrix element by an average for both initial and final orbital angular momenta, and forcing the planar reaction probabilities at each total angular momentum to be transferable to 3D, we use the 2DS-matrix to calculate the 3D helicity amplitude. Both differential and total reaction cross sections may be calculated from the helicity amplitude. The method is applied to the hydrogen exchange reaction in which the 2D scattering data (obtained via the distorted wave Born approximation) is converted to 3D and then compared with the results of other 3D calculations on the Porter-Karplus surface.

ISSN:0026-8976    

DOI:10.1080/00268977400101551

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The effect of interference or cross-correlation terms on the spin behaviour of a perturbed two-spin ½ system is analysed.

ISSN:0026-8976    

DOI:10.1080/00268977400101561

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The effect of the spatial variation of the dielectric constant across the air/water and metal/water interfaces on the energy of an ion in those regions is considered. This extends the recent work of Clay, Goel and Buff in two ways. Firstly, a single dielectric profile of finite range is constructed, for which analytic calculation of image potentials is possible. These solutions have a much simpler mathematical structure than those obtained by Clayet al.Secondly, the effect of the adjacent diffuse layer on image potentials at the metal/water interface is investigated. In all cases the answers are consistent with previous multiple imaging calculations on discontinuous interfaces, without the divergences at boundaries predicted by these models.

ISSN:0026-8976    

DOI:10.1080/00268977400101571

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor