bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Substituent on Crystal Structures of N-(Substituted- phenyl)-2,2,2-Trichloroacetamides, 2/3/4-XC 6 H 4 .NHCO.CCl 3 (X = Cl, NO 2 or CH 3 )
Authors: Thimme Gowda B. , Paulus Helmut , Fuess Hartmut
Published: February 2015

The crystal structures of N-(substitutedphenyl)-2,2,2-trichloroacetamides of the type 2/3/4-

XC6H4.NHCO.CCl3 (X = CI, NO2 or CH3), namely, N-(3-nitrophenyl)-2,2,2-trichloroacetamide,

3-NO2C6H4.NHCO.CCl3 (m-NO2PhTCA); N-(4-nitrophenyl)-2,2,2-trichloroacetamide,

4-NO2C6H4.NHCO.CCl3 (p-NO2PhTCA); N-(2-chlorophenyl)-2,2,2-trichloroacetamide,

2-ClC6H4.NHCO.CCl3 (o-ClPhTCA) and N-(4-chlorophenyl)-2,2,2-trichloroacetamide, 4-

C1C6H4.NHCO.CCl3 (p-ClPhTCA) have been determined at room temperature. The present

data are analysed along with our earlier crystal structures of N-(2-nitrophenyl)-2,2,2-trichloroacetamide,

2-NO2C6H4.NHCO.CCl3 (o-NO2PhTCA); N-(4-methylphenyl)-2,2,2-trichloroacetamide,

4-CH3C6H4. NHCO.CCl3 (p-CH3PhTCA); N-(phenyl)-2,2,2-trichloroacetamide,

C6H5.NHCO.CCl3 (PhTCA); N-chloro-N-(phenyl)-2,2,2-trichloroacetamide, C6H5.NClCO.CCl3

(NClPhTCA); and finally with N-(phenyl) acetamide, C6H5.NHCO.CH3 (PhA). The crystal type,

space group, formula units and lattice constants in Å of the new structures are; m-NO2PhTCA:

triclinic, PI, Z = 4, a = 7.493(3), b = 9.992(3), c = 15.225(5), α = 84.16(2)°, β = 82.59(2)°, γ =

84.92(2); p-N02PhTCA: monoclinic, P21/n, Z = 4, a = 5.807(2), b = 15.354(6), c = 12.475(5),

β = 92.28(2)°; o-ClPhTCA: orthorhombic, Pna21, Z = 4, a = 8.769(2), b = 12.838(3), c = 9.578(2)

and p-ClPhTCA: orthorhombic, Pbca, Z = 8, a = 9.742(4), b = 10.031(4), c = 23.110(9). The

compounds, m-NO2PhTCA, o-NO2PhTCA and p-CH3PhTCA show two molecules each in their

asymmetric units. This is in agreement with the multiple lines observed in the 35Cl NQR spectra

of the latter two compounds. But the presence of two molecules in the asymmetric unit of m-

NO2PhTCA indicates that it may undergoe a phase transition below room temperature. The bond

lengths and bond angles are normal except for some deviations. The presence of strong electron

withdrawing group at the ortho position of the phenyl ring and N-chlorination of the amide will

have significant effect on some bond distances and bond angles.
Study of High Frequency Relaxation Processes in Three Substances with the -CN Groups at the Lateral Positions
Authors: Urban Stanisław , Gestbloma Bo , Dąbrowskib Roman , Dziaduszekb Jerzy
Published: February 2015

Three liquid crystalline (LC) substances with the cyano-groups attached at the lateral positions to the molecular cores were studied with the aid of dielectric spectroscopy methods. The high frequency relaxation process connected with the molecular reorientations around the long molecular axes was studied in the isotropic, nematic and several smectic phases. The dielectric spectra are rather complex, indicating a contribution from several molecular processes to the main relaxation process. The dielectric time changes smoothly at the phase transitions between "liquid-like" phases (isotropic -nematic -smectic A -smectic C), and becomes shorter at the transition to the "solid-like" smectic G phase with a low-ering of the activation barrier. This indicates that the molecules perform broad angle librational motions rather than overall rotational motions in this phase. In case of a substance having two cyano groups at-tached to the benzene ring, a pronounced jump-wise change of the relaxation time was observed at the isotropic -smectic A transition.
Luminescence Properties of Some Coumarins with 3:4-Fused Ring System
Authors: Nikolov Peter , Petkova Ivan , Markov Peter
Published: February 2015

The photophysical characteristics of a group of coumarins with a 3:4-fused ring system (2-substitut-ed-4,5-dioxo-l,2-dihydro-4H,5H-pyrano-[3:4-c] [1]-benzopyrans) in solutions at room temperature, in frozen ethanol matrix at 77 K, in solid phase and in PVC films are reported. The low fluorescence quan-tum yield of the compounds investigated in solution is explained as a result of internal conversion from the fluorescent S2 (ππ*) state to the lower lying S1(nπ*) state. The phosphorescence with a life time in the order of seconds is connected with intersystem crossing S1 (nπ*) -T1(ππ*). The absorption Franck Condon transitions in solid phase and in PVC matrix are only weekly batochromically shifted accord-ing to solution.
Study of Li Diffusion on Metal and Semiconductor Surfaces via NQI Presented at the XVth International Symposium on Nuclear Quadrupole Interactions
Authors: Jänsch H. J.
Published: February 2015

Nuclear magnetic resonance has been used to study the diffusion of lithium on a Ru(001) single crystal surface. The quadrupolar interaction of the radioactive probe nucleus 8Li was utilized for this. In an online experiment the 8Li nuclei are produced, thermalized and highly polarized before they land on the surface studied, the parity violating β-decay revealing the sought after NMR/NQI nuclear information through the spatial asymmetry of the decay electrons. As a function of substrate temperature, alkali metal coverage and magnetic field the nuclear spin-lattice relaxation measurements show the existence of two distinctly different diffusion barriers on the surface, valued at 0.45 eV and 0.15 eV. The former is attributed to jumps from step to terrace sites, whereas the latter is the barrier between adjacent terrace sites. On the substrate Si(l 11)7x7 the relaxation measurements suggest a much higher diffusion barrier around 0.8 eV.
Two and Three Dimensional Nuclear Quadrupole Resonance in the Investigation of Structure and Bonding
Authors: Liao Ming-Yuan , Subramanian Raju , Yung Rachel L. , Harbison Gerard S.
Published: February 2015

A variety of two dimensional two-and three-dimensional NQR experiments are reviewed, showing their application to the determination of field gradients for important sites in peptides and proteins, for assigning connected transitions of nuclei with spin ≥ 5/2, and for determining hexadecapolar coupling constants. The quadrupole coupling tensor for 63Cu in the active site of a protein, bovine erythrocyte (Cu, Zn) superoxide dismutase, has been measured and is compared with the results of ab initio calculations.
Low Frequency NQR using Double Contact Cross-relaxation
Authors: Stephenson David , Smith John A. S.
Published: February 2015

A cross-relaxation technique is described which involves two spin contacts per double reso-nance cycle. The result is an improvement in signal to noise ratio particularly at low frequencies. Experimental spectra and analyses are presented: 14N in ammonium sulphate showing that the tech-nique gives essentially the same information as previous studies; 14N in ammonium dichromate determining e2Qq/h as (76±3) kHz and η = 0.84±.04; 7Li in lithium acetylacetonate for which the spectrum (corrected for Zeeman distortion) yields e2Qq/h = (152 ±5) kHz and η=.5 ±.2. Calculated spectra are presented to demonstrate the η dependence of the line shapes for 7Li.
The 8-Parameter List Mode for γ-γ Perturbed Angular Correlation Measurements
Authors: Marszałek M. , Grębosz Jerzy , Jaworski Jacek , Stachura Zbigniew , Sulkio-ClefP Bernd
Published: February 2015

A new TDPAC spectrometer which is based on the principle of event by event data acquisition (list mode) in order to reduce a background, avoid systematic errors and increase efficiency of the setup is described. The principal demand on the new spectrometer is the simultaneous measurement of all events containing the time and energy signals of the four detectors appearing in a preset common time window. For this purpose an 8-parameter list mode data acquisition system has been developed.
Quadrupole Effects on 73Ge NMR Spectra in Isotopically Controlled Ge Single Crystals
Authors: Verkhovskii S. V. , Malkin B. Z. , Trokiner A. , Yakubovskii A. , Haller E. , Ananyev A. , Gerashenko A. , Piskunov Yu. , Saikin S. , Tikhomirov A. , Ozhogin V.
Published: February 2015

NMR spectra of 73Ge (nuclear spin I = 9/2) in perfect single crystals of germanium with different isotopic content were measured at 80, 300, and 450 K. The observed specific line shapes gave evidence of the isotopic disorder, in particular, abnormal broadening of the spectrum was found for the magnetic field directed along the [111] axis. Local lattice deformations in the germanium crystal lattice due to "isotopic disorder" were calculated in the framework of the adiabatic bond charge model. The results were applied to study random non-cubic crystal field interactions with the nuclear quadrupole moments and corresponding effects on NMR spectra. The simulated second moment of the resonance frequency distributions caused by the magnetic dipole-dipole and electric quadrupole interactions are used to analyze the lineshapes, theoretical predictions being in a qualitative agreement with the experimental data.
Dynamic Behavior of Group 13 Elements in Bromocomplexes as Studied by NQR and NMR
Authors: Tomita Yasumasa , Ohki Hiroshi , Yamada Koji , Okuda Tsutomu
Published: February 2015

NMR, NQR, powder X-ray diffraction, DTA and AC conductivity were measured in RMBr4 (R = Ag, Cu; M = Al, Ga) and RM2Br7 (R = Li, Ag; M = Al, Ga). In RMBr4 , the activation energy of Cu+ diffusion was evaluated from 63Cu NMR and was in good agreement with that from 81Br NQR. In CuAlBr4 , the e2Qq/h value of 63Cu NMR and the η value of 27AI NMR changed linearly with decreasing temperature, although the e2Qq/h value of 27AI NMR did not change so much. These temperature dependences are supposed to be due to Cu+ diffusion and not to a variation of the lattice constants. In RM2Br7 , the activation energy was obtained from the spin-lattice relaxation time T1 of 81Br NQR and is ascribed to a modulation of the cation diffusion. The line width of 7Li NMR in LiAl2Br7 was about 5.9 kHz in the low-temperature phase and 0.4 kHz for the high-temperature phase. The 27AlNMR spectrum was broadened by the quadrupole interaction and unchanged up to 400 K, suggesting that diffusion of Li+ ions occurs in the high-temperature phase.
Search for Nucleation of Phase Embryos in Binary Alloys by Impurity Atoms
Authors: Collins Gary S. , Peng Luke S.-J. , Zacate Matthew O.
Published: February 2015

A search was made to detect the possibility that individual impurity atoms in two-phase, binary alloys nucleate embryonic crystals. The alloy system studied was Ni-Al and the impurities were 111ln probe atoms. Local surroundings of the probes characteristic of the crystal phases were detected through quadrupole interactions with 111Cd daughter nuclei using the method of perturbed angular correlation of gamma rays. Analysis of site fractions of the probes led to two alternative interpretations that could not be distinguished on the basis of the present measurements: 1.) 111ln probes in the two-phase domain between Ni2Al3 and NiAl segregate to Ni2Al3 with a segregation energy of about 0.10 eV; or 2.) 111ln probes nucleate embryonic crystals of Ni2Al3, with the driving force for nucleation being an attraction between In atoms and Ni vacancies that is known to be strong in NiAl.
NQR Investigation of Intercalates and Complexes of Cadmium and Lead Iodides with Pyridine, Aniline, and Piperidine
Authors: Babushkina T. A. , Konopleva K. G. , Tupoleva A. L. , Venskovskii N. U. , Guibé L. , Gourdji M. , Péneau A.
Published: February 2015

127I and 14N NQR have been investigated in two cadmium idodide -pyridine compounds, the inter-calate CdI2 +5.9 pyridine and the CdI2Py2 complex. In the intercalate, iodine is mainly ionic and nitro-gen like in pure pyridine; in the complex, iodine exhibits 30% covalency while nitrogen, coordinated to the central cadmium atom of the complex, and presents coupling constants e2Qq and η smaller than in pure pyridine. The difference between the two compounds is also revealed by the thermal coefficient of the quadrupole coupling constants and the relaxation. Results on the other title compounds are also given.
Crystal Structure and Phase Transition of 4-Aminopyridinium Tetrabromoantimonate(III) as Studied by Bromine and Antimony NQR, Proton NMR, and Single Crystal X-Ray Diffraction
Authors: Hashimoto Masao , Hashimoto Shinichi , Terao Hiromitsu , Kuma Masayuki , Niki Haruo , Ino Hiroyuki
Published: February 2015

The crystal structure of the room temperature phase (RTP) of the title compound was determined at 297 K (monoclinic, space group C2/c, a = 1384.2(2), b = 1377.8(3), c = 755.5(2) pm, β = 121.58(1)°). A complicated disorder was found for the cation. A phase transition from the low-temperature phase (LTP) to the RTP was found at (224 ±1) K (Tc). The 1H NMR spectra showed a sharp motional narrowing at ca. T=Tc , indicating the occurrence of a reorientational motion of the cation in the RTP in accord with the disorder. It was found that another reorientational motion is excited in the LTP. Four 81Br NQR lines (132.71, 115.38, 61.54 and 59.31 MHz at 77 K) and two Sb NQR lines (53.78 and 33.76 MHz at 77 K) were found in the LTP, while a single 81Br NQR line was observed at T> 276 K (ca. 121.80 MHz at 300 K). Crystal dynamics are discussed on the basis of the temperature dependence of the NQR, 1H NMR line width, and 1H NMR T1.
2H NMR Study of Molecular and Electron Spin Dynamics in Paramagnetic [Co(H2O)6][SiF6]
Authors: Iijima Takahiro , Mizuno Motohiro , Suhara Masahiko
Published: February 2015

The temperature dependences of 2H NMR spectra and the spin-lattice relaxation time T\ were measured for [Co(H2O)f,][SiF6]. The variation of the spectrum above room temperature can be explained by the reorientation of [Co(H2O)6]2+ about the C3 axis. The activation energy Ea and the jumping rate at infinite temperature K0 for the three site jump of [Co(H2O)6]2+ were obtained as 82 kJmol-1 and 2x 1017s-1 from the spectral simulation. Below room temperature, the spectral line shape was dominated by the 180° flip of the water molecule. The minimum of T1 caused by the 180° flip of the water molecule was observed at ca. 260 K. The jumping rate of the 180° flip of the water molecule was estimated from the 2H NMR T1 and the spectral simulation. Ea = 38 kJmol-1 and K0 = 6x 1015s-1 for the 180° flip of the water molecule were obtained from T1.
Quadrupole Splitting and Paramagnetic Iron Core Structure in Iron-Dextran Complexes: A Mössbauer Effect Study
Authors: Oshtrakh M. I. , Semionkin V. A. , Milder O. B. , Livshits A. B. , Kozlov A. A.
Published: February 2015

The pharmaceutical^ important iron-dextran complexes (ferritin models) were studied by Mössbauer spectroscopy in frozen solution at 87 K and in lyophilized form at 297 and 87 K. The quadrupole splittings of the lyophilized forms of iron-dextran complexes measured at 297 and 87 K were slightly different. The quadrupole splittings of several complexes in lyophilized form and frozen solutions measured at 87 K were also different. Slight differences in the quadrupole split-ting were found for various iron-dextran complexes. Mössbauer spectra of iron-dextran complexes were better fitted using two quadrupole split doublets. Slight differences in the corresponding quadrupole splittings and doublet ratios were observed for various complexes.
127I NQR and Crystal Structure Studies of [N(CH3)4]2 CdI4
Authors: Ishihara Hideta , Horiuchi Keizo , Gesing Thorsten M. , Dou Shi-qi , Buhl J.-Christian , Terao Hiromitsu
Published: February 2015

The temperature dependence of 127I NQR and DSC as well as the crystal structure at room temperature of the title compound were determined. This compound shows a first-order phase transition of an order-disorder type at 245 K. Eight 127I(v1:m = ±1/2 ↔ ±3/2) NQR lines of 79.57, 81.86, 82.56, 83.36, 84.68, 87.72, 88.34, and 88.86 MHz, and corresponding eight 127I(v2: m = ±3/2 ↔±5/2) NQR lines were observed at liquid nitrogen temperature. Three 127I(υi) NQR lines wfth an intensity ratio of 1:1:2 in the order of decreasing frequency were observed just above the transition point and two NQR lines except for the middle-frequency line disappeared around room temperature. This temperature behavior of NQR lines is very similar to that observed in [N(CH3)4]2Hgl4. Another first-order phase transition takes place at 527 K. The structure of the room-temperature phase was redetermined: orthorhombic, Pnma, Z = 4, a = 1342.8(3), b = 975.7(2), c = 1696.5(3) pm. The NQR result of three lines with an intensity ratio of 1:1:2 is in agreement with this structure. The thermal displacement parameters of atoms in both cations and anions are large.
FP-LAPW Study of the EFG at Impurity Sites in Oxides: Cd in Rutile TiO2
Authors: Errico Leonardo A. , Fabricius Gabriel , Rentería Mario
Published: February 2015

We report here first-principles determination of the electric-field gradient (EFG) tensor at the Cd im-purity located at cation sites in rutile TiO2 . As far as we know, these represent the first ab initio calcu-lations at impurity sites with the FP-LAPW method in oxide systems. We used super-cells to simulate the diluted impurity in the crystal. The free-relaxation process performed in our study shows that the changes in distances of the oxygen nearest-neighbours to the impurity are not isotropic as was suppo-sed in a previous study within the muffin-tin approximation. Our prediction for the EFG component of major absolute value agrees well with the experiment and is opposite in sign and direction if isotropic relaxations are assumed. Our value of the asymmetry parameter η also compares very well with the ex-perimental value.
47,49Ti NMR in Metals, Inorganics, and Gels
Authors: Bastow T. J.
Published: February 2015

Some recent progress in solid state 47,49Ti NMR is described and reviewed. The metallic-state work described covers metals such as hep titanium, TiB2 , a number of intermetallics such as TiAl2 and TiAl3· The inorganic work covers the various titanium oxide based materials including the TiO2 polymorphs, anatase, rutile and brookite. The gel work covers the evolution of crystalline titania from gels formed by hydrolysis of titanium isopropoxide. Some complementary data from 17O and 13C NMR and powder X-ray diffraction is also included.
Deuteron NMR Lineshapes in the Antiferroelectric Liquid Crystalline Phase of MHPOBC
Authors: Blinc R. , Gregorovič A. , Zalar B.
Published: February 2015

The deuteron NMR lineshapes in the tilted antiferroeelectric smectic liquid crystalline phases are evaluated for: i) the case of a discrete short pitch modulation P1 = N • d where N = 2,3,4, ii) for a superposition of two modulations p1 and p0 where p0 ≫p1 as well as iii) for the case where in addition rapid molecular exchange between adjacent layers takes place due to translational diffusion. The results are compared with the experimental deuteron NMR spectra of α-CD2 deuterated MHPOBC in the Sm C*
A phase measured at different angles between the magnetic field direction and the normals to the smectic layers. The alternating tilt structure of the Sm C*
A phase is confirmed
Investigation of the Negative Thermal Expansion of ZrW2O8
Authors: Ulbrich N. , Tröger W. , Butz T. , Blaha P.
Published: February 2015

The negative thermal expansion in ZrW2O8 was investigated on a microscopic scale by temperature dependent measurements of the electric field gradients at the nuclear probe 187W(β-) 187Re using time differential perturbed angular correlation spectroscopy. Two distinct nuclear quadrupole interactions I Vzz
Re1 l= 18.92(4) • 10 21 V/m2 , ηRe1 = 0.0 and I Vzz
Re1 l = 4.55(2) • 1021 V/m2 , ηRe1 = 0.053(3) were observed at 295 K, which are assigned to the two crystallographically distinct W0 4 tetrahedra of the room temperature structure. Ab initio calculations of electron densities and electric field gradients with 1:7 Re-impurities using the full potential linearized augmented plane wave package WIEN97 yield the electric field gradients Vzz
Re1 = 12.63 • 10 21 V/m2 , ηRe1 = 0.0 and Vzz
Re2 =4.90 • 10 21 V/m2 , ηRe2 =0.0. The observed temperature dependence of the nuclear quadrupole interactions agrees well with the structural phase transition at 428 K observed by neutron and x-ray diffraction. Our experiments corroborate the suggested mechanism of coupled librations of rigid ZrO6 octahedra and WO4 tetrahedra, which is an alternative description of transverse vibrations of oxygen atoms in Zr-O-W bonds, for the negative thermal expansion in ZrW2 O8
Combined TDPAC and EXAFS Study of InPt/FER Catalysts
Authors: Ramallo-López J. M. , Requejo F. G. , Bibiloni A. G. , Rentería M. , Gutierrez L. , Miró E. E.
Published: February 2015

Time Differential Perturbed Angular Correlation (TDPAC) experiments using 111In as probe were performed in order to determine the nature of In-sites in In-ferrierite (In/FER), before and after the incorporation of Pt through the hyperfine interaction between the nuclear quadrupole moment of the probe's nucleus and the extranuclear electric field gradient (EFG). Extended X-ray Absorption Fine Structure (EXAFS) measurements were performed to measure the absorbance above the Pt's LIII absorption edge in the transmission mode in order to determine the local environment of Pt atoms in Pt/FER and In Pt/FER catalysts. TDPAC spectra of 111In in In/FER and InPt/FER taken at 500°C in air indicated that there are no changes in the indium surroundings after the incorporation of Pt. Three sites were found for indium in both samples. Two of them correspond to the two sites of indium in ln2O3 and the third one is attributed to In in exchange sites of the zeolites. Their population, quadrupole frequencies and asymmetry parameters didn't change with the incorporation of Pt. EXAFS experiments showed similar near neighborhood Pt-0 distances and Pt coordination number in Pt/FER and In Pt/FER samples. There is no evidence of the presence of any In-Pt bimetallic entity in In Pt/FER catalyst.
Thiourea and Thiourea Inclusion Compounds. A14N NQR Investigation
Authors: Guibé L. , Péneau A. , Gourdji M. , Panich A.
Published: February 2015

A reinvestigation of the nitrogen-14 NQR in thiourea has permitted to record, apparently for the first time, the resonances above 169 K. The first order and second order of the transitions at 169 K and 202 K, respectively, appear clearly from the temperature dependence of the resonance frequencies; the modulated structure, incommensurate or commensurate, is also seen on the 14N NQR spectrum. This study is the first step of a new investigation of thiourea and its inclusion compounds.
A133Cs NMR Spin-Lattice Relaxation Study in Incommensurate Cs2CdI4
Authors: Suzuki Koh-ichi , Ishimaru Shin'ichi , Ikeda Ryuichi
Published: February 2015

133Cs NMR spin-lattice relaxation times(T1) in crystalline Cs2CdI4 were measured at 225 - 373 K. The critical exponent ( of T\ observed near the normal-incommensurate transition in the normal phase was determined to be 0.62 ± 0.03, in good agreement with the predicted value for three-dimensional XK-model. The frequency dependent T1 in the incommensurate phase could be explained by the fluctuation of amplitudon and small gap phason.
35Cl NQR Studies of Hydrogen Transfer in Crystalline p-Chlorobenzoic Acid
Authors: Nihei Taka-aki , Ishimaru Shin'ichi , Ikeda Ryuichi
Published: February 2015

35Cl NQR frequencies and spin-lattice relaxation times T1Q were measured in p-ClC6H4CO2H(PCB A) and p-ClC6H4CO2D(PCBA-d1) at 77-333 K. T1Q in PCB A gave a shallow minimum of 8.0 ms at ca. 110 K, which could be explained by a double proton transfer mechanism in the carboxylic acid dimer referring to 1H NMR data giving a T1H minimum at almost the same temperature. PCBA-d1, showed temperature dependent NQR frequencies quite analogous to those in PCBA, whereas their T1Q behaviour was quite different in its minimum value and its temperature as well as temperature gradient. These results were explained by suppressed deuteron tunnelling and the Ubbelohde effect.
Structure and Energetics of Clusters Relevant to Thorium Tetrachloride Melts
Authors: Akdeniz Z. , Tosi M. P.
Published: February 2015

We study within an ionic model the structure and energetics of neutral and charged molecular clusters which may be relevant to molten ThCl4 and to its liquid mixtures with alkali chlorides, with reference to Raman scattering experiments by Photiadis and Papatheodorou. As stressed by these authors, the most striking facts for ThCl4 in comparison to other tetrachloride compounds (and in particular to ZrCl4) are the appreciable ionic conductivity of the pure melt and the continuous structural changes which occur in the melt mixtures with varying composition. After adjusting our model to data on the isolated ThCl4 tetrahedral molecule, we evaluate (i) the Th2Cl8 dimer and the singly charged species obtained from it by chlorine-ion transfer between two such neutral dimers; (ii) the ThCl6 and ThCl7 clusters both as charged anions and as alkali-compensated species; and (iii) various oligomers carrying positive or negative double charges. Our study shows that the characteristic structural properties of the ThCl4 compound and of the alkali-Th chloride systems are the consequence of the relatively high ionic character of the binding, which is already evident in the isolated ThCl4 monomer.
Ground and Excited State Dipole Moments of LAURDAN Determined from Solvatochromic and Thermochromic Shifts of Absorption and Fluorescence Spectra
Authors: Kawski A. , Kukliński B. , Bojarski P. , Diehl H.
Published: February 2015

The electric dipole moments in the ground /µg and excited state of the fluorescent probe LAUR-DAN are determined from solvatochromic and thermochromic shifts to be /µg = 3.46 D, µe = 10.6 D and /µg = 3.76 D, /µe = 10.24 D, respectively. These values concern the free LAURDAN molecule. The val-ues of the dipole moments of LAURDAN (= 6-decanoyl-2-dimethylamine-naphthalene) exceed dis-tinctly those of PRODAN (= 6-propionyl-2-dimethylamine-naphthalene).
PVT Measurements on 3-Cyanobenzyl 2,5-bis(4-n-octyloxybenzoyl- oxy)benzoate up to 250 MPa and 423 K
Authors: Würflinger A. , Sandmann M. , Weissflog W.
Published: February 2015

P, Vm , T data have been measured for the nematic and isotropic phases of 3-cyanobenzyl 2,5-bis (4-n-octyloxybenzoyloxy)benzoate between 273 and 423 K and up to 250 MPa. The volume changes accompanying the crystal -nematic and nematic -isotropic transitions have been determined. The cor-responding enthalpy changes have been calculated using the Clausius-Clapeyron equation. The p, V m , T data enable also to estimate the volume entropy for the nematic-isotropic transition. It is found that the configurational part of the transition entropy amounts to 80%, this portion being distinctly larger than found in previous studies for conventional rod-like liquid crystals.
Photoisomerization of Triazine-stilbene Fluorescent Brighteners in Solution and in their Copolymers with Styrene
Authors: Grabchev Ivo , Bojinov Vladimir
Published: February 2015

The paper reports on the photochemical trans-cis isomerization of some new polymerizable triazine-stilbene fluorescent brighteners and their copolymers with styrene in aqueous and ethanol solutions. A dependence of trans-cis isomers in solution equilibrium and in solid polymeric films on the nature of the substituent in the triazine ring has been found.
Mean Amplitudes of Vibration of the Tetrafluorophosphite, PF4
−, Anion
Authors: Baran E. J.
Published: February 2015

Mean amplitudes of vibration of the pseudo-trigonal bipyra-midal PF4
−anion have been calculated from vibrational spectroscopic data in the temperature range between 0 and 1000 K. The results are briefly discussed in relation to the structural peculiarities of the anion and some comparisons with related species are made.
Comment on the Comment by G. Schäfer on the Paper "Non-kinematicity of the Dilation-of-time Relation of Einstein for Time-intervals" by S. Golden
Authors: Jefimenko O. D.
Published: February 2015

In his comment G. Schäfer [1] points out that S. Golden's [2] time-dilation equations (12) and (13) are of kinematic type and that the title of Golden's paper is therefore a misconception. He also states that Golden's treatment of the time-dilation problem is incomplete, since Golden has not considered particle decay in his paper. I should like to present my comment on these two points raised by G. Schäfer. Although Golden describes his equation (13) as "spatially dependent," he says at the beginning of Sect. 4 of his paper that his equations (12) and (13) can be regarded as "either velocity dependent or spatially dependent." But this is not at all the essence of his paper. The essence of his paper is that the two time-dilation equations that he has derived do not imply "any actual dilation-of-time in clocks that may be stationed in the systems." Hence he concludes that Einstein's time-dilation relation is merely a transformation relation and that the motion of the systems does not affect "the intrinsic time-rates of any clocks stationed within them." In order to judge the significance of Golden's paper, it is important to remember that Einstein arrived at the ideas of kinematic time-dilation and length contraction in moving systems not as a result of a rigorous deduction from any mathematical, physical or logical relations, but simply by interpreting in his own way the physical significance of transformation equations for space and time (Lorentz transformation equations) [3]. Ever since the publication of his 1905 article, Einstein's ideas of kinematic length contraction and time dilation
Sending Signals to Space-Like Separated Regions
Authors: Aharonov Y. , Vaidman L.
Published: February 2015

Two recent works suggest a possibility of sending signals to a space-like separated region, contrary to the spirit of special relativity. In the first work (J. Grunhaus, S. Popescu, and D. Rohrlich, Phys. Rev. A 53, 3781 (1996)) it has been shown that sending signals to a particular union of space-like separated regions cannot cause causality paradoxes. Another work (Y. Aharonov and L. Vaidman, Phys. Rev. A 61, 052108 (2000)) showed that the relative phase of the quantum superposition of a particle at two separate locations can be measured locally. Together with the possibility of changing the relative phase in a nonlocal way using the potential effect we, apparently, have a method of sending signals to space-like separated regions. These arguments are critically analyzed in this paper.
Young's Experiment, Schrödinger's Spread and Spontaneous Intrinsic Decoherence
Authors: Bonifacio R. , Olivares S.
Published: February 2015

The two slits interference pattern for single particle is revisited, showing its strict relation to the free particle Schrödinger’s spread and describing the optical analogy. We explicitly show the possibility that spontaneous intrinsic decoherence (SID) can destroy interference pattern and that decoherence becomes stronger at the macroscopic limit.
Quantum Physics and Reality
Authors: Haag Rudolf
Published: February 2015

Apparent paradoxes in Quantum Physics demand a sharp distinction between a "real part of the world" and the realm of possibilities. In the former we may distinguish individual elements (coarse events) relating to space-time, with causal connections between them respecting the relativistic locality principle. The latter, quantitatively described by probability assignments conditioned on existing facts and depending on the definition of equivalence classes of situations, cannot be subdivided in space-time categories. There are global correlations (Pauli principle...). The cut between the realms of facts and possibilities implies an evolutionary picture of the "real world" in which the (generalized) arrow of time assumes basic significance. Some deficiencies of existing theory are pointed out.
Frequent Observations Accelerate Decay: The anti-Zeno Effect
Authors: Kofman A. G. , Kurizki G.
Published: February 2015

The quantum Zeno effect (QZE) is the striking prediction that the decay of any unstable quan­ tum state can be inhibited by sufficiently frequent observations (measurements). The consensus
The Paradoxes of the Interaction-free Measurements
Authors: Vaidman L.
Published: February 2015

Interaction-free measurements introduced by Elitzur and Vaidman [Found. Phys. 23,987 (1993)] allow finding infinitely fragile objects without destroying them. Paradoxical features of these and related measurements are discussed. The resolution of the paradoxes in the framework of the Many-Worlds Interpretation is proposed.
Decoherence, Classical Properties and Entanglement of Quantum Systems
Authors: Blanchard Ph. , Olkiewicz R.
Published: February 2015

We discuss the properties of decoherence and its role in the appearance of classical properties in open quantum systems. In particular, it is used for classification of pure states with respect to their ability to persist despite the environmental monitoring.
Maximally Entangled Mixed States and the Bell Inequality
Authors: Munro W. J. , Nemoto K.
Published: February 2015

Recently a class of maximally entangled states has been proposed that has the maximum amount of entanglement for a given purity. We investigate how much such states violate the conventional Bell inequality and discuss its implication.
Interaction-Free Which-Path Information and Some of Its Consequences
Authors: Ryff Luiz Carlos
Published: February 2015

Let us consider a single particle in an interferometer. If one of the two possible paths is blocked and the particle is detected, we know that the particle has followed the path which is not blocked. This would be an interference-free "which-path" information experiment. However, we no longer have an interfe­rometer, since one path is blocked. An alternative is to interact with the particle, but this would change its momentum and as a consequence the interference fringes would disappear, as discussed by Feynman. We can also consider two particles entangled in direction. Knowing the path followed by one of the par­ticles, it is possible to know the path followed by the other. On the other hand, when this information is erased, interference can be observed. However, this is a two particle interference: no single particle inter­ference can be observed. Retrodiction experiments are also possible, but these are not conclusive. Here we propose a much less intuitive experiment in which, without blocking one path or directly interacting with the particle, it is possible to know the path which is being followed by the particle in the interferom­eter. According to quantum mechanics, this is sufficient to lose the single particle interference. The same idea can be used to test the local pilot wave interpretation, to test quantum nonlocality under new conditions, and to devise an interferometer for a two-photon wave packet. This last result strongly suggests that there must be some connection between the deBroglie wavelength of an N-particle wave packet and entanglement. Wavelength of an /V-particle Wave Packet.
Non-Collinear Configuration for Dichromatic Squeezing
Authors: Andreoni Alessandra , Bondani Maria , D ’Ariano G. Mauro , Paris Matteo G. A.
Published: February 2015

We propose a non-collinear experimental scheme for the joint generation of two amplitudesqueezed beams at the frequencies u\ and u>2, fundamental and second harmonics of a Nd:YAG laser pulse. The scheme consists of two successive steps, both involving second-order non-linear interactions in ß - BaB2O4 non-linear crystals. One of the output beams show subPoissonian photon statistics, and this allows to use photodetection instead of homodyne detection for diagnostics
Against Quantum Nonlocality
Authors: Baere W. De , Neve J. De
Published: February 2015

It is shown that all quantum “contradictions” disappear if one drops the assumption of unique initial conditions for a hidden variable theory for individual quantum processes. Our proposal corresponds with a deterministic world evolution such that local physical conditions are nonreproducible, in agreement with empirical observation
Nonlocal de Broglie Wavelength of a Two-Photon System
Authors: Fonseca E. J. S. , Paulinia Zoltan , Nussenzveig P. , Monkena C. H. , Padua S.
Published: February 2015

We show that it is possible to associate a de Broglie wavelength to a composite system even when the constituent particles are separated spatially. The nonlocal de Broglie wavelength (A /2) of a two-photon system separated spatially is measured with an appropriate detection system. The two-photon system is prepared in an entangled state in space-momentum variables. - Pacs: 42.50.-p, 42.50.Ar
Flopping between Schrödinger's Cat States
Authors: Frasca Marco
Published: February 2015

We show that for an atom in a cavity in the strong coupling regime, flopping between Schrödinger cat states, devised as a superposition of displaced number states, can be accomplished. Beside, the Rabi frequency can be set to zero, so that population trapping or localization can be accomplished. These states could be proved to be useful for quantum computation
Bohm's Mysterious 'Quantum Force' and 'Active Information': Alternative Interpretation and Statistical Properties
Authors: Lan Boon Leong
Published: February 2015

An alternative interpretation to Bohm’s ‘quantum force’ and ‘active information’ is proposed. Numerical evidence is presented, which suggests that the time series of Bohm’s ‘quantum force’ evaluated at the Bohmian position for non-stationary quantum states are typically non-Gaussian stable distributed with a flat power spectrum in classically chaotic Hamitonian systems. An important implication of these statistical properties is briefly mentioned
Decoherence and Universality of a Quantum Phase Gate
Authors: Mancini Stefano , Bonifacio Rodolfo
Published: February 2015

We study the dephasing noisy effects on a Quantum Phase Gate and the consequences on its universality. To this end we employ two frameworks displaying their differences and analogies. Pacs: 03.67.Lx, 03.65.Bz
The Domain of the Quantum Matter Wave
Authors: Mills B.
Published: February 2015

In quantum mechanics a particle is represented by a complex wave function. This is similar to the classical description of a distributed particle by a real valued density function. However, while classically the combined density of multiple particles can be decomposed into individual densities; the wave function of a multi-particle system can not always be decomposed into wave functions for the individual particles. Hence the classical assumption that density is a property of physical space, which is only possible because of the special topology of classical configuration space, does not work for quantum systems.
Bell Inequalities with Schrödinger Cats
Authors: Reid M. D.
Published: February 2015

In the Schrödinger cat gedanken experiment a “cat” is in a quantum superposition of two macroscopically distinct states. There is the apparent interpretation that the “cat” is not in one state or the other, “alive” or “dead”. Here this interpretation is proved objectively. I propose the following definition of macroscopic reality: first, that the “cat” is either dead or alive, the measurement revealing which; second, that measurements on other “cats” some distance away cannot induce the macroscopic change, “dead” to “alive” and vice versa, to the “cat”. The predictions of quantum mechanics are shown to be incompatible with this premise.
Twin-beams Statistics for Strong Pumping
Authors: Porzio A. , Sciarrino F. , Chiummo A. , Solimeno S.
Published: February 2015

Twin-beams generated by non degenerate optical parametric oscillators exhibit squeezing in the inten­ sity difference. Here we report intensity noise correlation and single beam spectra for pump power up to 14 times the threshold value. The degree of correlation of the two beams is practically independent of pump level. The single beam spectra confirm presence of relaxation oscillation.
QSES's and the Quantum Jump
Authors: Salgado David , Sánchez-Gómez José Luis
Published: February 2015

The stochastic methods in Hilbert space have been used both from a fundamental and a practical point of view. The result reported here concerns the application of these methods to model the evolution of quantum systems and does not enter into the question of their fundamental or practical status. It can easily be stated as follows: Once a quantum stochastic evolution scheme is assumed, the incompatibility of the Markov property with the notion of quantum jumps is easily established
Theoretical Studies of the g Factors for Co2+ in MgO and CaO Crystals
Authors: Wu Shao-Yi , Zheng Wen-Chen
Published: February 2015

This paper presents a cluster approach to the calculation of the g factors for 3d7 ions in cubic oc­ tahedral crystals, in which the parameters related to the configuration interaction and the covalency reduction effects are obtained from optical spectra of the studied crystals, and so no adjustable parameters are applied. From the approach, the g factors for MgO:Co2+ and CaO:Co2+ are cal­culated. The calculated results show good agreement with the observed values. The experimental values of g 4.333 for CaO:Co2+ are also explained.
Spin-lattice Coupling Coefficient G44 of KMgF3:Mn2+ Calculated from Two Cases
Authors: Wu Shao-Yi , Zheng Wen-Chen
Published: February 2015

The high (fourth) order perturbation formulas based on the dominant spin-orbit coupling mech­anism for the zero-field splittings Dtri of a 6S-state ion in trigonal symmetry and Erho in rhombic symmetry are derived from the strong field scheme. Two analytic expressions of the spin-lattice coupling coefficient G44 obtained from the formulas of and Erho are established by using a simple and uniform method. Based on the two expressions, the coefficients G44 for KMgF3:Mn2+ are calculated in two cases. The results show that the lowest (third) order perturbation formulas of D(3)
tri and E(3)
rho are too simple and too approximate to give reasonable and consistent values of G44, whereas when the fourth-order perturbation terms D(4)
tri and E(4)
rho are considered, the calculated values of G44 (= G(3)
44 + G(4)
44) in both cases are not only close to each other, but also in agreement with the observed value. So, the fourth-order perturbation terms cannot be neglected.
The Elastic Constants of Nematic n-Hexylcyanobiphenyl Determined with the Capacitance Method
Authors: Czechowski G. , Czerkas S. , Jadżyn J.
Published: February 2015

The splay (K 11) and bend (K 33) elastic constants of n-hexylcyanobiphenyl (C6H13-Ph-Ph-C=N) were determined from the voltage (U) dependence of the capacitance (C) of the planar nematic cell with a small molecular pretilt angle. The capacitance changes are due to distortion of the director n driven by the applied electric field. K 11 was obtained from the Freedericksz threshold voltage (Uth) and K 33 from the C(U) dependence above the threshold voltage by means of the method proposed by Gruler et al. and Uchida et al. The significance of the pretilt angle in the determination of K 33 is discussed.
Thermodynamic Measurements on Selected Liquid Crystals at Normal and Elevated Pressures
Authors: Schmalfuss H. , Weissflog W. , Würflinger A. , Masberg S. , Schneider G. M.
Published: February 2015

Densities have been determined for two 5-n-alkyl-2-(4-isothiocyanatophenyl)-1,3-dioxanes (6DBT, 10DBT), 4-n-tetradecyl-4'-cyanobiphenyl (14CB), 4-n-octyl-4'-thiocyanatobiphenyl (8BT) and two laterally aryl-branched mesogens 4-cyanobenzyl 5-(4-n-octyloxybenzoyloxy)-2-undecyloxybenzoate (4CNOUB), 3-cyanobenzyl 2,5-bis(4-n-octyloxybenzoyloxy)benzoate (3CN-BOB). The densities have been measured in the isotropic, nematic (only 3CNBOB) and smectic phases with a vibrating tube densimeter. The densities decrease with increasing alkyl chain length within a homologous series. Furthermore the enthalpy changes accompanying the phase transitions have been determined by DSC.
Estimation of the Enrichment of Cs in Molten Chloride and Fluoride Systems by Molecular Dynamics Simulation
Authors: Matsumiya Masahiko , Takagi Ryuzo
Published: February 2015

For the pyrochemical reprocessing of spent metallic fuels in molten salt baths it is of importance to estimate the enrichment degree of Cs. A molecular dynamics simulation has been executed on molten (Li, Na, Cs)Cl at 900 K and (Li, Na, Cs)F at 925 K for various compositions in order to calculate the relative differences in the internal cation mobilities of Cs in molten LiCl-NaCl equimolar mixtures and the LiF-NaF eutectic. According to these results the self-exchange velocities of Li+, Na+ and Cs+ with respect to Cl- and F- have similar tendencies at each composition, and Cs can be enriched effectively up to xCs = 0.5 -0.6 in LiCl-NaCl melts. In addition, the sequence of the calculated self-diffusion coefficients for various compositions was in a fair agreement with that of the obtained self-exchange velocities.
Nuclear Magnetic Resonance Study of Caesium-133 in Binary Molten Trifluoroacetate Salt Mixtures
Authors: Mirny V. N. , Trachevski V. V. , Mimaya T. A.
Published: February 2015

The chemical shifts of Cs+ in binary melts of caesium trifluoroacetate with lithium, sodium, potassium or thallium trifluoroacetates have been studied as a function of composition. An influence of added foreign cations on chemical shift of caesium nuclei has been found. The nature of the intra-and intermolecular paramagnetic contributions into the shifts of 133Cs is discussed.
Spectral Properties of 3-Benzanthrone Derivative Dyes in Isotropic Solvents, Polymer Film and Liquid Crystal
Authors: Grabchev I. , Moneva I. , Wolarz E. , Bauman D. , Stoyanov S.
Published: February 2015

Some recently synthesized benzanthrone derivatives bearing azomethine and oxy groups at C-3 po­ sition have been systematically studied. The influence of the substituents and of the environment (iso­ tropic and anisotropic media) on the absorption and fluorescence of the dyes and their vibronic transi­ tions is discussed in this paper.
Ab initio Molecular Orbital Calculations of Reduced Partition Function Ratios of Hydrated Lithium Ions in Ion Exchange Systems
Authors: Yanase Satoshi , Oi Takao
Published: February 2015

Molecular orbital (MO) calculations at the HF/6-31G(d) level were carried out for the aquolithium ions, Li+(H2O)n (n = 3, 4, 5, 6, 8, 10 and 12) and the aquolithium ions interacting with the methyl sul­fonate ion (MeS-), Li+MeS-(H2O)n (n = 0, 3,4, 5, 6, 7, 8 and 10) which were, respectively, intended to be substitutes for lithium species in the solution and resin phases of ion exchange systems for lithium isotope separation. For each of the species considered, at least one optimized structure with no negative frequency was obtained, and the 7Li-to-6Li isotopic reduced partition function ratio (RPFR) was esti­mated for the optimized structure. The solvation number in the primary solvation sphere was four, both in the solution and resin phases; three waters and MeS" formed the primary solvation sphere in the res­ in phase. Additional water molecules moved off to the secondary solvation sphere. It was found that consideration on the primary solvation sphere alone was insufficient for estimations of reduced parti­tion function ratios of aquolithium ions. Although the agreement between the experimentally obtained lithium isotope fractionation and the calculated results is not satisfactory, it is pointed out that the HF/6-31 G(d) level of the theory is usable for elucidation of lithium isotope effects in aqueous ion exchange systems.
On Statistics of Graph Energy
Authors: Graovac Ante , Gutman Ivan , John Peter E. , Vidović Dušica , Vlah Ivana
Published: February 2015

The energy EG of a graph G is the sum of the absolute values of the eigenvalues of G. In the case whene G is a molecular graph, EG is closely related to the total π-electron energy of the corresponding conjugated molecule. We determine the average value of the difference between the energy of two graphs, randomly chosen from the set of all graphs with n vertices and m edges. This result provides a criterion for deciding when two (molecular) graphs are almost coeneigetic.