Volume 43, Issue 2

An information theoretical description is given of the action of 1D maps on probability measures (e.g. on ergodic invariant measures of chaotic maps). On the basis of a detailed analysis of the elements of information flow the problem of optimum measuring of initial states for state predictions is discussed. Moreover, we give an information theoretical description of the relaxation, under the action of a map, of an initial probability distribution to any, not necessarily steady, final distribution. In this connection we formulate an H-theorem for 1D maps.

Absorption spectra in the far and intermediate infrared, as well as Raman and vibronic spectra were measured for three crystalline forms of four-ligand europium chelate with dibenzoylmethane and piperidine and a three-ligand chelate in the spectral ranges: 40-450, 450-4500, 0-4500 and 0-1600 cm - 1 , respectively. The analysis of the individual spectra enabled the identification of the frequencies corresponding to the vibrations of the Eu -O bond coupled with the lattice vibrations, and the frequencies of the intraligand vibrations. It is found that piperidine is bound to the complex molecule by hydrogen bond.

A new experiment in the foundations of quantum mechanics is proposed. The existence of correlated photons -first seen by Wheeler -can be taken as a hint to devise a ‘‘double-wing’’ delayed choice experiment in Wheeler’s sense. A path choice (polarization choice) measurement made on the one side should then block an interference type measurement made on the other side (‘‘distant choice’’). A precondition for the combined measurement to work in theory is that the correlated photons used are of the ‘‘prepolarized’’ (Selleri) rather than the ‘‘unpolarized’’ (Böhm) type. A first EPR experiment involving prepolarized photons was recently performed by Alley and Shih. It may be used as a partial experiment within the proposed experiment.

The curves The curves Ω k , marking the frequency thresholds for type III separation in the parameter space of Poincaré halfmaps, are investigated further analytically. In the limit of great values of their argument, the relaxation constant ϱ, all frequency functions Ω k are shown to grow algebraically -each with the same exponent being ⅔. Furthermore, a perturbation expansion is presented that yields good results already at a level of approximation where the calculations can be performed analytically.

Using a rotating disc electrode, the dissociation rate of acetic acid in various aqueous electrolyte solutions is studied. Li + , Cs + and (CH 3 ) 4 N + at 1 M concentration considerably modify the activation enthalpy and entropy of the reaction. Evidently the interaction between the cations and water influences the dissociation mechanism of the weak acid. In the presence of 1 molar Li + the activated complex of acetic acid seems to contain only one water molecule instead of two in the other cases.

This paper describes a method for a simple evaluation of the polarization energy in molten salt systems, by which it is possible to go, without heavy computational cost, from the rigid to the soft ion model. The method is based on the observation that, within the movements of single ions in the Monte Carlo chain, the deviation of the polarization energy is a linear function of the deviation of the Coulomb energy. An extended numerical application has been carried out for molten Lil at 800, 1200 and 1453 (b. p.) K. The parameters that are mostly affected by the used model are put into evidence.

The first rotational transition of cyanogen iodide- 15 N (IC 15 N) has been investigated by microwave Fourier transform (MWFT) Stark effect spectroscopy to determine the electric dipole moment. In addition the first four rotational transitions have been measured by MWFT spectroscopy to obtain accurate parameters for the rotational, quadrupole and spin-rotation coupling parameters.

We determined the internal rotation barrier V 3 = 3.285 kcal/mol (13.74 kJ/mol) and the moment of inertia Iα = 3.184 amuÅ 2 of the methyl groups from the ground state microwave spectrum of 2-fluoropropane. Additionally the rotational constants, the quartic and some sextic centrifugal distortion constants are reported. The analysis of the Stark effect leads to the dipole moment 1.958 D.

The intermolecular interaction for ammonia-lithium ion has been investigated based on the LCAO-MO-SCF method, with double zeta basis set including polarization. The potential functions were constructed firstly from 50 ammonia configuration. Then 50 additional random configurations were added to test the quality of the function. The results show that even 100 configurations are not enough to obtain convergency, but the quality of the function obtained by well-selected points of the surface is already sufficient for simulation purposes.

The carbon -fluorine bond length and the distortion of the benzene ring under fluorination have been determined by the isotopic substitution method for 1,2-difluorobenzene. -The experimental work was carried out predominantly by Double Resonance Modulation (DRM) microwave spectroscopy, which allowed the spectra of all 13 C-forms to be studied in their natural abundance. The normal and the 4,5-d 2 species were used as parent molecules, and the two sets of structure results are found to agree well with each other. With square brackets indicating consistency limits between the two sets of results, the following bond distances (in Å) and angles (in degrees) have been obtained: C(1/2) - F(1/2) = 1.3494[4] ≮ C(1) C(2) F(2) = 119.16[1] C(1) - C(2) = 1.3755[3] ≮ C(1) C(2) C(3) = 121.17[2] C(2/1) -C(3/6) = 1.3786 [3] ≮ C(2) C(3) C(4) = 118.59 [2] C(3/6) - C(4/5) = 1.4004 [3] ≮ C(3) C(4) C(5) = 120.24 [1] C(4) - C(5) = 1.3917 [6] ≮ C(2) C(3) H(3) = 119.58 [1] C(3/6) -H(3/6) = 1.0829 [1] ≮ C(3) C(4) H(4) = 119.55 [1] C(4/5) - H(4/5) = 1.0813 [4]

The carbon -fluorine bond length and the distortion of the benzene ring under fluorination have been determined by the isotopic substitution method for 1,3-difluorobenzene. -The experimental work was carried out predominantly by Double Resonance Modulation (DRM) microwave spec­ troscopy, which allowed all C 13 -forms to be studied in their natural abundances. The normal and the 2,4,6,-d 3 species were used as the parent molecules, and the resulting two sets of structure parameters are found to agree well with each other. With square brackets indicating consistency limits between the two sets of results deduced by the Kraitchman method, the following bond distances (in Å) and angles (in degrees) have been found: C(1/3) - F(1/3) = 1.3561 [9] ≮ C(1) C(2) C(3) = 115.74 [6] C(2) - C(1/3) = 1.3888 [1] ≮ C(2) C(3) C(4) = 123.70 [5] C(113) - C(6/4) = 1.3745 [7] ≮ C(3) C(4) C(5) = 118.00 [2] C(4/6) - C(5) = 1.3956 [1] ≮ C(4) C(5) C(6) = 120.86 [1] C(2) - H(2) = 1.0822[3] ≮ C(1) C(2) H(2) = 122.13 [3] C(4/6) - H(4/6) = 1.0820 [2] ≮ C(3) C(4) H(4) = 119.92 [1] ≮ C(2) C(1) F(1) = 117.26 [7] ≮ C(4) C(5) H(5) = 119.57 [1] The bond lenth C(5) - H(5) was assumed as 1.082 ± 0.001 Å.

A fast neutron data acquisition system involving a curved position-sensitive proportional counter is described. The system permits simultaneous measurement of diffraction data over an angular range of 130 degrees at moderate resolution. Data for amorphous carbon are compared with x-ray diffraction data. Structure functions derived from the different methods are in good agreement. Amorphous carbon is a useful standard for the comparison of diffraction data from different laboratories.

Temperatures up to ~ 5 x 10 4 o K have been obtained with water vortex Gerdien arcs, and temperatures of ~ 105oK have been reached in hydrogen plasma arcs with magnetic thermal insulation through an externally applied strong magnetic field. It is suggested that a further increase in arc temperatures up to 10 6 o K can conceivably be attained by a combination of both techniques, using a Gerdien arc with a supersonic hydrogen gas vortex.

Partial structure factors and atomic distribution functions for liquid Fe 75 B 25 were determined for the Fe-Fe and Fe-B pairs by means of X-ray and neutron diffraction. The experimental results show a strong chemical short-range order in the melt which is similar to that of amorphous Fe 75 B 25 .

The anomalous X-ray scattering (AXS) technique was applied to a structural study of GeO 2 glass, using synchrotron radiation and a new goniometer system. The environmental radial distribution function (RDF) was determined from intensity measurements at the Ge K absorption edge and compared with the ordinary RDF curve estimated from the. X-ray scattering intensity by Mo K α radiation. By combining the environmental and ordinary RDFs of the GeO 2 glass it has been confirmed that the fundamental local unit structure is a GeO 4 tetrahedron and that these tetrahedra are joined at their corners to form a network structure. The capability of the AXS technique has been approved as a relatively new tool for the structural characterization of disordered materials.

The temperature dependences of the second moment and spin-lattice relaxation time of 1 H and 19 F NMR were measured on ammonium trifluorostannate (II) NH 4 SnF 3 . It was found that the NH 4 + ions having a C 3 symmetry in the crystal undergo overall reorientations with an activation energy of 22 kJ mol - 1 .