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Facet   Publication Year 1988  [X]
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1988[X]
21Author    Joachim Gripp, Helmut DreizlerRequires cookie*
 Title     
 Abstract    h e M ic ro w a v e S p e c tr u m o f C y a n o g e n I o d i d e -15N : H y p e rfin e S tr u c tu r e a n d E le c tric D ip o le M o m e n t In v e s tig a te d by M ic ro w a v e F o u r ie r T r a n s f o r m S p e c tr o s c o p y The first rotational transition of cyanogen iodide-15N (IC15N) has been investigated by microwa­ ve 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. 
  Reference    Z. Naturforsch. 43a, 133—137 (1988); received November 27 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0133 
 Volume    43 
22Author    Michael Meyer, Helmut DreizlerRequires cookie*
 Title     
 Abstract    h e G r o u n d S t a t e M ic ro w a v e S p e c tru m o f 2 -F lu o r o p r o p a n e We determined the internal rotation barrier V 3 = 3.285 kcal/mol (13.74 kJ/mol) and the moment of inertia Ix = 3.184 amuÄ2 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. 
  Reference    Z. Naturforsch. 43a, 138—142 (1988); received November 27 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0138 
 Volume    43 
23Author    SupotV. Hannongbua1, SiriratU. Kokpol1, Suchada Kreawsrikul, Supa Polman, BerndM. Rode1Requires cookie*
 Title      
 Abstract    te r m o le c u la r P o te n tia l F u n c tio n f o r A m m o n ia -L ith iu m Io n B a se d o n A b -in itio C a lc u la tio n s 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. 
  Reference    Z. Naturforsch. 43a, 143—146 (1988); received November 19 1987 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0143.pdf 
 Identifier    ZNA-1988-43a-0143 
 Volume    43 
24Author    OttoL. Stiefvater, Adran Cemeg, Coleg Prifysgol, Gogledd Cymru, Bangor, U. K. WalesRequires cookie*
 Title      
 Abstract    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 spec­ troscopy, which allowed the spectra of all 13C-forms to be studied in their natural abundance. The normal and the 4,5-d2 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 Ä) and angles (in degrees) have been obtained: C(1/2) — F (1/2) = 1.3494[4] * C(l)C(2) F(2) = 119.16[1] C(l) — 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] 
  Reference    Z. Naturforsch. 43a, 147—154 (1988); received October 5 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0147 
 Volume    43 
25Author    OttoL. Stiefvater, Adran Cemeg, Coleg Prifysgol, Gogledd Cymru, Bangor, U. K. WalesRequires cookie*
 Title      
 Abstract    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 C13-forms to be studied in their natural abundances. The normal and the 2,4,6,-d3 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 Ä) and angles (in degrees) have been found: C (l/3)-F(l/3) = 1.3561 [9] * C(l) C(2) C(3) = 115.74 [6] C(2) — C(l/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(l) 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 Ä. 
  Reference    Z. Naturforsch. 43a, 155—163 (1988); received October 5 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0155 
 Volume    43 
26Author    B. K. Annis, A. H. NartenRequires cookie*
 Title     
 Abstract    e u tro n D if fr a c tio n S tu d y o f A m o rp h o u s C a r b o n w ith a F a s t D a t a A c q u is itio n S y s te m * 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. 
  Reference    Z. Naturforsch. 43a, 164—168 (1988); received November 19 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0164 
 Volume    43 
27Author    F. WinterbergRequires cookie*
 Title     
 Abstract    u p e rs o n ic V o rte x G e r d ie n A rc w ith M a g n e tic T h e r m a l I n s u la tio n Temperatures up to ~ 5 x 104oK 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 106 C K can conceivably be attained by a combination of both techniques, using a Gerdien arc with a supersonic hydrogen gas vortex. 
  Reference    Z. Naturforsch. 43a, 169—176 (1988); received March 11 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0169 
 Volume    43 
28Author    N. Mattern3, W. M. Atzb, H. Hermann3Requires cookie*
 Title      
 Abstract    Partial structure factors and atomic distribution functions for liquid Fe75 B25 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 Fe75 B25. Key words: liquid Fe-B -X-ray, neutron diffraction on liquid Fe-B -partial structure factors of liquid Fe-B -partial atomic distribution functions of liquid Fe-B -short-range order in liquid Fe-B. P a r t i a l A to m ic D is tr ib u tio n F u n c tio n s o f L iq u id F e 75 B 25 
  Reference    Z. Naturforsch. 43a, 177—180 (1988); received November 16 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0177 
 Volume    43 
29Author    K. Matsubara, Y. Harada, Waseda, M. IwaseRequires cookie*
 Title     
 Abstract    The anomalous X-ray scattering (AXS) technique was applied to a structural study of Ge02 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 a radiation. By combining the environmental and ordinary RDFs of the Ge02 glass it has been confirmed that the fundamental local unit structure is a Ge04 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. A n o m a lo u s X -r a y S c a tte r in g S tu d y o f G e 0 2 G la s s 
  Reference    Z. Naturforsch. 43a, 181—186 (1988); received November 16 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0181 
 Volume    43 
30Author    Kiyofumi Hirokawa, Yoshihiro FurukawaRequires cookie*
 Title    'H and 19F NM R Study of Ammonium Ion Motion in Ammonium Trifluorostannate (II)  
 Abstract    The temperature dependences of the second moment and spin-lattice relaxation time of 'H and 19FNMR were mea­ sured on ammonium trifluorostannate (II) NH4SnF3. It was found that the NH4 ions having a C3 symmetry in the crystal undergo overall reorientations with an activation energy of 22 kJ mol"1. 
  Reference    Z. Naturforsch. 43a, 187—188 (1988); received October 10 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0187_n 
 Volume    43 
31Author    Michael Schindler, Marinus KunstRequires cookie*
 Title    Karl  
 Abstract    The influence of the excess charge carrier injection mechanism on the excess charge carrier dynamics in ZnO powder is investigated by contactless transient photoconductivity measurements. Excess charge carriers were produced by above bandgap light, subbandgap light and by injection from an adsorbed dye (Rhodamine B) after excitation of this dye. In all these cases the transient photoconductivity decay extends over a large time range but only after band-to-band excitation an appreciable decay is observed in the microsecond time range. The experimental results are discussed in particular with respect to photocatalysis. Keywords: Transient photoconductivity, sensitization, charge carrier kinetics, ZnO, photocatalysis. S e n s itiz a tio n a n d C h a r g e C a r r ie r K in e tic s in Z n O P o w d e rs 
  Reference    Z. Naturforsch. 43a, 189—192 (1988); received December 15 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0189 
 Volume    43 
32Author    Z. Gryczyński, A. KawskiRequires cookie*
 Title     
 Abstract    ir e c tio n s o f th e E le c tro n ic T r a n s itio n M o m e n ts in D io x id o -p -te r p h e n y l * The directions of the absorption, fluorescence and phosphorescence transition moments of dioxido-p-terphenyl are determined from measurements of the absorption and emission anisotropies as functions of the dichroic ratio in stretched PVA films. 
  Reference    Z. Naturforsch. 43a, 193—195 (1988); received January 18 1988 
  Published    1988 
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 Identifier    ZNA-1988-43a-0193 
 Volume    43 
33Author    Ilona Merke, Helmut DreizlerRequires cookie*
 Title      
 Abstract    Power spectra are commonly used in microwave Fourier transform spectroscopy. We point out distortions, which may lead to erroneous frequency measurements. D is to r tio n s in P o w e r S p e c tr a 
  Reference    Z. Naturforsch. 43a, 196—202 (1988); received December 11 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0196 
 Volume    43 
34Author    J. Haekel, H. MäderRequires cookie*
 Title     
 Abstract    e te rm in a tio n o f S p e c tr a l P a r a m e te r s in M ic ro w a v e F o u r ie r tr a n s f o r m S p e c tro s c o p y by A n a ly s is o f T im e -D o m a in S ig n a ls Some disadvantages of using the Fouriertransform algorithm to obtain rotational spectra from microwave pulse induced transient signals are demonstrated. To overcome the difficulties, a fitting procedure is suggested which is based on the analysis of time-resolved data. 
  Reference    Z. Naturforsch. 43a, 203—206 (1988); received November 11 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0203 
 Volume    43 
35Author    E. M. Borschel, M. BubackRequires cookie*
 Title     
 Abstract    im e riz a tio n o f C a r b o x y lic A c id s in S o lu tio n up to H ig h P r e s s u r e s a n d T e m p e r a tu r e s . 3. A c e tic A c id Acetic acid in dilute solutions of n-heptane and of CC14 is studied via IR spectroscopy in the region of the C = 0 and O —H stretching fundamentals at pressures up to 2250 bar and temperatures up to 150°C. Lambert-Beer's law is shown to be valid for the C = 0 modes of the acid monomer and of the hydrogen-bonded cyclic dimer in both solvents, which enables the quantitative measurement of the dimerization equilibrium as a function of pressure and temperature. The pressure dependence of dimerization enthalpy and the temperature dependence of dimerization volume are reported and are compared with direct information on the monomer and cyclic dimer species as derived from their O —H fundamental modes. 
  Reference    Z. Naturforsch. 43a, 207—214 (1988); received November 27 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0207 
 Volume    43 
36Author    Flemming Winther, Ursula Heyne, Antonio GuarnieriRequires cookie*
 Title      
 Abstract    A total number of 24 bands of the carbon disulfide isotopomers 32S212C, 34S12C32S, 33S12C32S, 34S212C, 32S213C, and 34S13C32S between 1555 and 1455 cm"1 have been investigated. Vibrational frequencies and rotational constants have been determined for the bands. 
  Reference    Z. Naturforsch. 43a, 215—218 (1988); received December 17 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0215 
 Volume    43 
37Author    T. Lalowicz, Ulrike Werner, W. Müller-WarmuthRequires cookie*
 Title      
 Abstract    Tunnelling frequencies of rotating CD3 groups in solids between about 20kHz and 2 MHz may be obtained from the 2H NMR spectra. The theory of the spectral response is developed where quadrupole and dipole-dipole interactions as well as rotational tunnelling are taken into account. Features characteristic of tunnelling, which distinguish the spectra from those of rapidly reorienting deuterated methyl groups, are found from analytically calculated spectra even for the case of very large tunnel splittings. Numerical calculations have been performed for various conditions to deter­ mine the tunnel frequency. Experimental spectra measured at 45 MHz and low temperatures have revealed the appearance of rotational tunnelling in CD3I, CD3COONa, and (CD3COO)2Cu • H20. In the latter case, a tunnelling frequency of 608 kHz has been extracted from the spectrum at 27 K. R o ta tio n a l T u n n e llin g o f C D 3 G r o u p s in M o le c u la r C r y s ta ls a s S tu d ie d by N M R S p e c tr a 
  Reference    Z. Naturforsch. 43a, 219—227 (1988); received January 13 1988 
  Published    1988 
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 Identifier    ZNA-1988-43a-0219 
 Volume    43 
38Author    Marek Koniński, RomanF. NalewajskiRequires cookie*
 Title     
 Abstract    C o m p a ra tiv e S tu d y o f A p p r o x im a te T r e a tm e n ts o f th e D e n s ity P o la r iz a tio n in The simple perturbative description of the main polarization effects in molecular systems is tested and calibrated using the modified Hamiltonian MNDO SCF results for the cyano group CN~ perturbed by positive or negative point charges. The relative importance of various polarization channels is examined and the reliability of the MNDO predictions is investigated by testing them against the respective ab initio modified Hamiltonian results. It is shown that the ^-function approximation of the point-charge perturbative potential leads to semiquantitatively correct density relaxation patterns, already within one-channel approximation. 
  Reference    Z. Naturforsch. 43a, 228—232 (1988); received November 21 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0228 
 Volume    43 
39Author    Ataru Kobayashi, Yoshichika Yoshioka, Nobuo Nakamura, Hideaki ChiharaRequires cookie*
 Title     
 Abstract    u c le a r M a g n e tic a n d Q u a d r u p o le R e s o n a n c e S tu d ie s o f P h a s e T ra n s itio n s in C r y s ta llin e (N H 4) 2S b F 5 a n d (N D 4) 2S b F 5 (NH4)2SbF5 undergoes two successive phase transitions at 169 and 292 K, both of which are of typical lambda-type and without thermal hysteresis. Proton and fluorine spin-lattice relaxation time measurements showed that the isotropic reorientation of the NH4 ions is highly excited below the lower transition point with an activation energy of 15.5 kJ mol"1 and that the uniaxial reorientation of the square pyramidal SbF5 2-anion is excited above about 200 K with an activation energy of 42.0 kJ mol-1. There is strong cross relaxation between the proton and the fluorine over the whole temperature range of the measurements. The 121Sb and Sb nuclear quadrupole resonance fre­ quencies show an anomalous temperature dependence; each resonance frequency assumes a mini­ mum at around 100 K and increases on heating, reaches a maximum at the lower transition point, decreases drastically in the middle temperature phase and then fades out just below the upper transition point. The anomalous increase in the resonance frequencies stems from the reorganization of the N — H ... F type hydrogen bonds with the progress of the lower phase transition. The lower and the upper transition temperatures shift to 173.0 and 290.1 K, respectively, on deuteration of the ammonium ion. 
  Reference    Z. Naturforsch. 43a, 233—238 (1988); received November 13 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0233 
 Volume    43 
40Author    C. Sartori, W. PreetzRequires cookie*
 Title     
 Abstract    e s 13C -und 180 -m a r k i e r t e n tr a n s -D io x o te tr a c y a n o o s m a ts (V I), | 0 S 0 2(C N) 4| 2 ~ Vibrational Fine Structure of the Electronic Spectra of 13C and 18O labelled trans-Dioxotetracyanoosmate (VI), [0s02(C./V)4]2~ The electronic absorption spectrum of the solid tetramethyl-ammonium salt of [0s02(CN)4]2_ is measured at 10 K. The five distinct band systems exhibit vibrational progressions in the range 660-750 cm"1, corresponding to the 0s = 0 stretching vibrations sometimes coupled with v(OsC). From this vibrational fine structure the electronic origin is deduced and verified by characteristic isotopic shifts by lsO and 13C. The two bands at lowest energy are assigned to the d-d-transitions >Alg [b2g] 3Eg [b'g e1] (620 -460 nm) and *Alg [b2g] 1Eg [b^g e1] (490 -400 nm). The 3Eg state is split by spin-orbit coupling into 5 components, from the one at lowest energy a luminescence emission (830 — 670 nm) takes place with a progression of 860 cm-1, corresponding to the symme­ tric Os —O stretching vibration in the electronic ground state. The more intense bands are assigned to charge transfer transitions from oxo 7t-orbitals into unoccupied niveaus of Os (VI): xAlg K) -» 3A2u [e3 e1] (390 -340); lAlu [e3 e,1] (340 -290) and -> JEU [e3 bjj (290 -230 nm). The singlet-triplet distances are 3200-3600 cm l. From a Franck-Condon analysis an excited state elongation of 10-13 pm for the osmyl groups is calculated. D ie S c h w in g u n g s fe in s tr u k tu r d e r E le k tr o n e n s p e k tre n 
  Reference    Z. Naturforsch. 43a, 239—247 (1988); eingegangen am 22. December 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0239 
 Volume    43 
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