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Volume 39 Issue 5

Issue of Zeitschrift für Naturforschung A

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Open Access June 2, 2014

Triplet States in Isotopically Mixed Naphthalene Crystals: High Resolution Optical Spectroscopy

U. Doberer, H. Port

Page range: 413-426

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Abstract

The triplet 0.0 transitions (T 1 ↔ S 0 ) of guest and host in various isotopically mixed naphthalene crystals, with guest states below and above the host exciton band, are investigated applying both laser excitation spectroscopy and phosphorescence emission spectroscopy. Guest monomer and aggregate spectra are analyzed at helium temperatures (1.6-4.2 K) with regard to line positions, splittings, polarizations and intensities. Shift and broadening of the host Davydov components are studied as a function of the guest concentration (at 1.6 K). In particular, the analysis provides precise values for the individual isotopic shifts U 0 and the exciton band structure parameters including the critical isotopic shift. Site splitting is spectrally resolved for several monomers and also for the AB-dimer of 1,4-Nd 2 in Nd 8

Open Access June 2, 2014

Mechanism of the Effect of a Resonant Microwave Field on Triplet-Triplet Annihilation Between Unlike Triplet Species

L. Pasimeni

Page range: 427-433

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Abstract

The intensity of the DF-ODMR spectrum has been derived when unlike triplets contribute to the annihilation process (heterofusion). Resonant microwave transitions that perturb the spin levels of the triplet pair and of the species diffusing separately (free species) were considered. In the latter case the DF-ODMR signals are negative at any orientation of the magnetic field. The spectra of single crystals of the Diphenylacetylene(DPA)-TCNB complex support the theoretical expectations

Open Access June 2, 2014

Optical Absorption Spectra of Phosphonyl Radicals

T. Sumiyoshi, A. Henne, P. Lechtken, W. Schnabel

Page range: 434-436

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Abstract

Upon UV-irradiation, various phosphine oxides of the general structure I were found to be fragmented readily into free radicals I′ and I″ Laser flash photolysis studies revealed that radicals of type I" with R 2 and/or R 3 being phenyl groups possess a strong absorption band with a maximum around 330 nm. ε 335nm = 1.9×10 4 1/mol cm was estimated for diphenyl phosphonyl radicals (Ph 2 P = O).

Open Access June 2, 2014

Structure Investigation into Acetonitrile Solutions of Mg(ClO₄)₂ by Neutron Diffraction

U. Hoppe, W. Matz

Page range: 437-440

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Abstract

The structure of acetonitrile solutions of Mg(ClO 4 ) 2 at two concentrations (c = 0.38 mole/1 and 0.74 mole/1) is studied by neutron diffraction. The results are interpreted by a simple structure model. A good description is achieved for c = 0.38 mole/1 by an octahedral surrounding of Mg 2+ by acetonitrile molecules. For the higher concentration the fit results in a mixture of tetrahedral and octahedral surroundings

Open Access June 2, 2014

On the Connection of Nonrenormalizable and Renormalizable Unified Nonlinear Spinor Field IVfodels

H. Stumpf

Page range: 441-446

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Abstract

The nonrenormalizable first order derivative nonlinear spinor field equation with scalar interaction possesses two equivalent Hamiltonians. The first is the conventional one while the second is a two-field Hamiltonian with the original field and its parity transform. By quantization the latter leads to an inequivalent representation compared with the former. This is connected with parity symmetry breaking and the loss of simultaneous diagonalization of energy and subfield particle numbers. The corresponding grand canonical Hamiltonian is shown to result equivalently from a renormalizable second order derivative nonlinear spinor field equation. This is achieved by means of a theorem about the decomposition of higher order derivative nonlinear spinor field equations derived previously

Open Access June 2, 2014

Low-pressure Noble Gas Broadening of the Cs Resonance Lines

F. Siegling, K. Niemax

Page range: 447-454

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Abstract

The wings of the Cs resonance line (6 2 S 1/2 - 6 2 P 1/2, 3/2 ) broadened by noble gases (He, Ne, Ar and Kr) at low pressures (p ≦ 700 Torr) have been measured in absorption in the range 4 up to a few hundred wavenumbers from the line centres. The far wings are compared with quasistatic wings based on the semiempirical potentials by Baylis and by Pascale and Vandeplanque. In some cases the agreement between the experimental and theoretical line wings is found to be reasonable

Open Access June 2, 2014

High-Pressure Noble Gas Broadening of the Cs Resonance Lines

F. Siegling, K. Niemax

Page range: 455-463

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Abstract

The noble gas broadening (Ar and Kr) of the Cs resonance lines 8944 and 8521 Å (6 2 S 1/2 -6 2 P 1/2, 3/2 ) was measured in absorption up to perturber pressures of about 20 atm. The experimental shapes of the 8944 Å line induced by multiperturber interaction are compared with theoretical shapes calculated by means of the quasistatic theory assuming additivity of the A 2 Π 1/2 - X 2 Σ 1/2 difference potential energies

Open Access June 2, 2014

X-Ray Diffraction Study of MgCl₂ in Methanol

T. Radnai, E. Kálmán, K. Pollmer

Page range: 464-470

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Abstract

The structure of a concentrated solution of MgCl 2 in methanol has been studied by X-ray diffraction. The parameters for the ion-solvent interactions are in good agreement with those found in aqueous solutions. Both for Mg 2+ and Cl - the solvate shells are composed of 6 methanol molecules. An average octahedral arrangement of OH groups in the solvate shells of magnesium is probable. Octahedral symmetrical positions for CH 3 groups proved to be unlikely

Open Access June 2, 2014

Association in Molten Salts and Mobility Isotherms

A. Klemm

Page range: 471-474

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Abstract

A change with concentration in the height of the first peak of the pair distribution function g + - of a salt in a mixture of molten salts indicates a change in the degree of association of that salt. It is shown that the changes in association observed this way from MD-simulations of binary mixtures of charge symmetric salts with a common anion are qualitatively consistent (i) with the requirements for the occurrence of the crossing of mobility isotherms (Chemla effect) and (ii) with the ideal law of mass action

Open Access June 2, 2014

Electric Field-Induced Birefringence in Liquid-Crystalline Blue Phases

F. Porsch, H. Stegemeyer, K. Hiltrop

Page range: 475-480

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Abstract

The optical behaviour of liquid-crystalline 'Blue Phases' (BP) of polar cholesterogenic compounds in electric Fields up to 100 kV • cm -1 has been investigated by means of polarization microscopy. By an observation parallel to the field direction a birefringence dependent on the Field strength was detected in the BP I. This result is discussed in terms of a non-linear electrooptic effect, showing that the BP I becomes optically biaxial in an electric field. In the BP II a birefringence was not observed under the same conditions probably indicating that the field induces an optical uniaxiality with the optic axis parallel to the field. The results are discussed with respect to possible cubic structures of the BPs

Open Access June 2, 2014

Quantitative Analysis of the Intensity of Interference Fringes of X-Ray Diffraction Line Profiles

K. Häupl, P. Wißmann

Page range: 481-485

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Abstract

X-Ray diffraction spectra of thin films may show characteristic interference fringe patterns which wash out with increasing surface roughness. From the intensity of the secondary maxima quantitative data on the roughness can be derived. Model calculations are presented assuming that the distribution of heights about the mean surface level is Gaussian. The theory is applied to explain the diffraction spectra of single-crystal silver films. It is shown that some uncertainty in the results remains due to the influence of lattice distortions

Open Access June 2, 2014

Semiempirische Rechnungen zur Protonenaffinitat unverzweigter aliphatischer Amine / Semiempirical Calculations on the Proton Affinity of Unbranched Primary Aliphatic Amines

Gerhard Raabe, Jörg Fleischhauer

Page range: 486-489

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Abstract

The experimental gasphase proton affinities of some alkylamines are found to correlate with the Mulliken charges on the NH 3 -groups of the corresponding ammonium-cations as calculated by the semiempirical MINDO/3- and MNDO-method rather than with the electron density at the nitrogen-atom or the NH 2 -group of the corresponding Amines. As can be seen from the charges of the NH 2 -groups of the amines, the alkyl-chains do not exhibit a general positive inductive effect. It is found that the amount of electron density transferred to an attacking proton increases with the length of the alkyl-chains. This effect is similar to the so-called inductomeric effect introduced by Ingold

Open Access June 2, 2014

Photolumineszenz und Energietransfer in Seltenerd-aktivierten Granat Gd₃Te₂Li₃O₁₂ / Photolwninescence and Energy Transfer in the Rare Earth Activated Garnet Gd₃Te₂Li₃O₁₂

B. Köngeter, S. Kemmler-Sack

Page range: 490-494

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Abstract

By activation of the cubic garnet host lattice Gd 3 Te 2 Li 3 O 12 with trivalent rare earth ions the most intense visible emission is observed for Ln 3+ = Eu, Tb. Energy transfer from Gd 3+ to Sm 3+ , Eu 3+ or Dy 3+ , from Tb 3+ to Eu 3+ and from Er 3+ to Tm 3+ has been found to occur. The luminescence properties are strongly influenced by the substitution of Te 6+ by W 6+ (systems Gd 3-x Ln x Te 2-y W y Li 3 O 12 )

Open Access June 2, 2014

The Rotational Barrier About the Disulphide Bridge in Dimethyl Disulphide: An Ab Initio Study

V. Renugopalakrishnan, R. Walter

Page range: 495-498

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Abstract

An ab initio molecular orbital technique was used to investigate the rotational barrier about the disulphide bridge in dimethyl disulphide. Various minimal and extended basis sets were used in the calculations. The chosen minimal basis set was the STO-3G set, and the extended basis sets were the STO 4-31G set, the Dunning and Hay set consisting of contracted Gaussian basis sets: [2s], [3s, 2p] and [6s, 4p] for H, C, and S atoms, and the Dunning and Hay basis set augmented with a d-type function on S atoms. The total energy was calculated as a function of the torsion angle about the disulphide bond. The barrier to rotation about this bond was found to be two-fold in nature, in accordance with previous findings. The heights of the barriers were observed to depend upon the basis set and input geometry. For our particular choice of basis sets and input geometry, the calculated value of the eis and trans barriers ranged from 12.68 to 16.49 kcal/mol and from 6.23 to 8 kcal/mol, respectively. Inclusion of a d-type function in the basis sets was found to result in better agreement between the calculated and experimental values, thereby emphasizing the need for considering 3d orbitals of sulphur in MO calculations

Open Access June 2, 2014

Determination of the Stability of the AIO⁺ Complex in Alkali Halide Melts*

C. M. Wai, M. Blander

Page range: 499-502

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Abstract

The solubilities of Al 18 2 O 3 in LiCl-KCl eutectic mixtures containing dissolved AlCl 3 were measured using a sensitive proton activation technique. The results are consistent with the presence of an A10 + species at 4.7 x 10 -5 mole fraction with AlCl 3 at 10 -2 mole fraction. When combined with other thermodynamic data, these solubilities are used to deduce a formation constant for the A10 + species from Al 3+ and O 2- ions of 1.94 x 10 22 (in mole fraction units) and a specific bond free energy ("bond strength") of 300 kJ mol -1

Open Access June 2, 2014

A Simplified Form of the Hermitianizing Matrix for the Half Integer Spin Bhabha Fields

C. G. Koutroulos

Page range: 503-506

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Abstract

The hermitianizing matrix of the Bhabha fields for s = half integer can be simplified to the form f(x, s) = (-1) s-p-1/2 and as a result the charge of these fields for s > 1/2 is indefinite

Open Access June 2, 2014

Mikrokristallbildung und intermolekulare Triplett-Triplett-Energieiibertragung in festen transparenten Glasern bei 77 K. Das System N-Methylcarbazol/Naphthalin / Microcrystal Formation and Intermolecular Triplet-Triplet Energy Transfer in Rigid Transparent Glasses at 77 K. The System N-Methyl-earbazole / Naphthalene

M. Zander

Page range: 507-508

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Abstract

The efficient intermolecular triplet-triplet energy transfer between N-methylcarbazole (donor) and naphthalene (acceptor) observed at 10 -2 ᴍ concentration of donor and acceptor in a rigid transparent methylcyclohexane/n-pentane glass at 77 K is shown to occur in microcrystals of the donor containing small amounts of the acceptor

Open Access June 2, 2014

The Relaxation Time of the Orientation Polarization and its Influence on the Luminescence Intensity Distribution*

A. Kawski

Page range: 509-510

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Abstract

The characteristic relaxation time τ R of the orientation polarization of polar solvent molecules around polar luminescent molecules influences the spectral emission distribution depending on τ F > τ R or τ F ≦ τ R . This is shown on the luminescence of the polar molecules 4-isocyanate- 4'-dimethylamino-transstilbene (CDS), 4-isocyanate- 4'-methoxy-trans-stilbene (CMS) and 4-isocyanate- 3',4'-dimethoxy-trans-stilbene (CDMS) (having a very short lifetime τ F < 10 ps) in chlorobenzene

Open Access June 2, 2014

Stark Effect Measured by Microwave Fourier Transform Spectroscopy

W. Kasten, W. Stahl, H. Dreizler

Page range: 511-512

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Abstract

We present the test measurements with a Stark cell for Microwave Fourier Transform Spectroscopy, which is precise enough to improve the measurement of dipole moments

About this journal

Objective
A Journal of Physical Sciences: Zeitschrift für Naturforschung A (ZNA) is an international scientific journal which publishes original research papers from all areas of experimental and theoretical physics. Authors are encouraged to pay particular attention to a clear exposition of their respective subject, addressing a wide readership. In accordance with the name of our journal, which means “Journal for Natural Sciences”, manuscripts submitted to ZNA should have a tangible connection to actual physical phenomena. In particular, we welcome experiment-oriented contributions.

Manuscripts considered for publication in A Journal of Physical Sciences: Zeitschrift für Naturforschung A undergo high-level refereeing. Mere formal correctness of a paper is not sufficient for its acceptance. Moreover, articles reporting a merely marginal extension of already existing knowledge are considered unsatisfactory. Instead, the key quality a publication in A Journal of Physical Sciences: Zeitschrift für Naturforschung A should possess is that it makes a genuine contribution to the advancement of its topic.

Topics

Atomic, Molecular & Chemical Physics
Dynamical Systems & Nonlinear Phenomena
Gravitation & Cosmology
Hydrodynamics
Quantum Theory
Solid State Physics & Materials Science
Thermodynamics & Statistical Physics

Article formats
Original research articles, research notes, letters and review articles from all areas of theoretical and experimental physics

Information on submission process

Volume 39 Issue 5

Issue of Zeitschrift für Naturforschung A

Triplet States in Isotopically Mixed Naphthalene Crystals: High Resolution Optical Spectroscopy

Abstract

Mechanism of the Effect of a Resonant Microwave Field on Triplet-Triplet Annihilation Between Unlike Triplet Species

Abstract

Optical Absorption Spectra of Phosphonyl Radicals

Abstract

Structure Investigation into Acetonitrile Solutions of Mg(ClO4)2 by Neutron Diffraction

Abstract

On the Connection of Nonrenormalizable and Renormalizable Unified Nonlinear Spinor Field IVfodels

Abstract

Low-pressure Noble Gas Broadening of the Cs Resonance Lines

Abstract

High-Pressure Noble Gas Broadening of the Cs Resonance Lines

Abstract

X-Ray Diffraction Study of MgCl2 in Methanol

Abstract

Association in Molten Salts and Mobility Isotherms

Abstract

Electric Field-Induced Birefringence in Liquid-Crystalline Blue Phases

Abstract

Quantitative Analysis of the Intensity of Interference Fringes of X-Ray Diffraction Line Profiles

Abstract

Semiempirische Rechnungen zur Protonenaffinitat unverzweigter aliphatischer Amine / Semiempirical Calculations on the Proton Affinity of Unbranched Primary Aliphatic Amines

Abstract

Photolumineszenz und Energietransfer in Seltenerd-aktivierten Granat Gd3Te2Li3O12 / Photolwninescence and Energy Transfer in the Rare Earth Activated Garnet Gd3Te2Li3O12

Abstract

The Rotational Barrier About the Disulphide Bridge in Dimethyl Disulphide: An Ab Initio Study

Abstract

Determination of the Stability of the AIO+ Complex in Alkali Halide Melts*

Abstract

A Simplified Form of the Hermitianizing Matrix for the Half Integer Spin Bhabha Fields

Abstract

Abstract

The Relaxation Time of the Orientation Polarization and its Influence on the Luminescence Intensity Distribution*

Abstract

Stark Effect Measured by Microwave Fourier Transform Spectroscopy

Abstract

Structure Investigation into Acetonitrile Solutions of Mg(ClO₄)₂ by Neutron Diffraction

X-Ray Diffraction Study of MgCl₂ in Methanol

Photolumineszenz und Energietransfer in Seltenerd-aktivierten Granat Gd₃Te₂Li₃O₁₂ / Photolwninescence and Energy Transfer in the Rare Earth Activated Garnet Gd₃Te₂Li₃O₁₂

Determination of the Stability of the AIO⁺ Complex in Alkali Halide Melts*