bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-dimensional Two Contact Double Resonance Spectroscopy
Authors: Stephenson David
Published: February 2015

A two-dimensional spectroscopic technique is presented. Application of the technique to de-termine all the relaxation rates for a multi-level quadrupole system is discussed along with ex-perimental requirements. Theoretical and experimental data are analyzed for the 14N, three level, spin 1 system. The analysis shows that all three relaxation rates can be obtained from a single two-dimensional spectrum, and that only 3 peaks in the 3 x 3 two-dimensional intensity matrix are needed to completely specify the problem. The 4-level spin 3/2 system is also examined. In theory, all six relaxation rates can be independently evaluated (for a suitable system) without necessitating measurement at the low frequency Zeeman separated levels.
Effect of Deuteration on Ammonium Motion and Structural Phase Transition Studied by Nuclear Quadrupole Resonance
Authors: Asaji Tetsuo , Ishizaka Tomohiro
Published: February 2015

35Cl NQR measurements revealed two phase transitions at 14.5 K and 70 K in NH4ICI4. By deuteration of the ammonium ions, the respective transition temperature increased to 27 K and 74 K. In the lowest-temperature phase of NH4ICI4, by the deuteration a remarkable change of the temperature dependence of the 35Cl NQR frequencies was observed. The NQR spin-lattice relaxation-time minimum, ascribable to the modulation effect of the electric field gradient (EFG) due to a motion of the ammonium ions, was observed at 7 K and 11 K in NH4ICl4 and ND4ICI4, respectively. The activation energy of the ammonium motion and the fluctuation fraction q' /q of the EFG were determined to be 0.32 kJ mol-1 and 1.3x10-3 for NH4ICI4, and 0.30 kJ mol-1 and 0.88x10-3 for ND4ICI4. The experimental result suggests that the inter-ionic interaction between the ammonium ion and the ICl4
- complex anion is weakened by the deuteration. However, the frequency shift observed in the lowest-temperature phase is much larger in ND4ICI4 than in NH4ICI4. This suggests that the lattice distortion in NH4ICI4 is suppressed to a great deal by the tunneling rotation of NH4
+ ions. The effective inter-ionic interaction responsible for the lattice distortion, the transition temperature and the enhancement of tunneling of NH4
+ as compared with ND4
+ is discussed for NH4ICI4 as well as for previously reported NH4AuCI4 and α-NH4HgCl3.
Pressure Dependence of the Chlorine NQR in Chloro Pyridines
Authors: Ramesh K. P. , Ramakrishna J. , Suresh K. S. , Rao C. Raghavendra
Published: February 2015

The 35CI NQR frequency (υQ) and spin lattice relaxation time (T1
) in 2,6-dichloropyridine, 2 amino 3,5-dichloropyridine and 6 chloro 2-pyridinol have been measured as a function of pressure up to 5.1 kbar at 300 K, and the data have been analysed to estimate the temperature coefficients of the NQR frequency at constant volume. All the three compounds show a non linear variation of the NQR frequency with pressure which can be described by a 2nd order polynomial in pressure. The rate of change of the NQR frequency with pressure is positive and decreases with increasing pressure. The spin lattice relaxation time T
1, in all the three compounds shows a small increase with pressure, indicating that the relaxation is mainly due to the torsional motions.
External Influences on the 14N NQR of Ferroelectric NaNO2
Authors: Choh Sung Ho , Jung Jae Kap
Published: February 2015

External influences on the 14N NQR of ferroelectric NaNO2, such as changes of the temperature, electric field, stress, gamma-ray irradiation, and impurity doping are reviewed. They normally cause either a frequency shift or a broadening of the 14N NQR lines and are strongly related to the change of the spontaneous polarization.
The Temperature Dependence of 121,123Sb, 35Cl, 79,81Br and 127I NQR Spectra in Complexes Cs3Sb2X9 (X = Cl, Br, I)
Authors: Zemnukhova L. A. , Kuznetsov S. I. , Fedorishcheva G. A. , Davidovich R. L.
Published: February 2015

The 123,123Sb, 35Cl, 79,81Br and 127I NQR Spectra of the complexes Cs3Sb2X9 (X = Cl, Br, I), prepared from CsX and SbX3 aqueous solutions, were studied at 77-400 K. Analysis of the^ temperature coeffi-cients of the quadrupole transition frequency (v), quadrupole coupling constant (e2Qqzz) and asymme-try parameter of the electric field gradient (η) was carried out.
Weakly Coordinating Ligands: Nuclear Quadrupole Coupling Constants and Asymmetry Parameters of Iodocarbons Coordinated to Metal Ions
Authors: Wulfsberg Gary , Robertson Joyce , Babushkina T. A. , Gushchin S. I. , Terao Hiromitsu , Powell John
Published: February 2015

NQR (nuclear quadrupole resonance) spectroscopy is potentially one of the best ways of characterizing the bonding of metal cations such as zirconocene cations and Ag+ to halogen donor atoms in weakly coordinating anions and neutral ligands such as halocarbons. Known coordination of organoiodine atoms to silver ions was studied by 127I NQR spectroscopy in [Ag(p-C6H4I2)](PO2F2), [Ag(o-C6H4I2)]N03 , [Ag(CH2I2)2]PF6, and the explosive [Ag(CH2I2)]NO3 ; a possible case of iodocarbon coordination to a mercury atom in C5Cl5HgCl ·CH2I2 was also investigated. Both the low-frequency (ca. 300 MHz) and the high-frequency (ca. 500 MHz) NQR signals were detected for each compound, and, for the first time, the quadrupole coupling constants e2Qqzz/h and asymmetry parameters ηof coordinated organohalogen atoms were obtained. As compared to the free iodocarbons, substantial (4 - 12%) reductions of e2Qqzz/h and substantial increases in η (to about 20 - 40%) were found in the iodocarbon complexes of silver, but not of mercury. From approximate theoretical analysis of the data, it appears that the electronic interaction of silver and iodine is quite substantial.
111Cd Time Differential Perturbed Angular Correlation Studies of High Specific Activity 111In-Aqueous Solutions
Authors: Akselrod Z. Z. , Filossofov D. V. , Buša J. , Bušova T. , Kochetov O. I. , Lebedev N. A. , Novgorodov A. F. , Pavlov V. N. , Salamatin A. V. , Shirani E. N. , Timkin V. V.
Published: February 2015

Time-differential PAC measurements have been made using the high specific activity of 111In, both in aqueous solutions of the ClO-
4 , NO-
3 and Cl- at pH values between 1.0 and 9 and temperatures between 186 and 293 K.
PAC Identification of Electric-Nuclear-Quadrupole Interactions in Sm-Sesquioxides
Authors: Rentería M. , Errico L. A. , Bibiloni A. G. , Freitag K. , Requejo F. G.
Published: February 2015

We present Perturbed Angular Correlation (PAC) results of the electric-nuclear quadrupole interaction at lxl Ta located at the nonequivalent cation sites of cubic C-Sm2O3 and monoclinic B-Sm2O3 free of defects. The application of the empirical Cd/Ta correlation found in binary oxides allowed us to correlate the interactions with each site and to identify the single Sm site populated in 111In-implanted B-Sm2O3 experiments. The preferential site occupation of Cd and Ta in B-Samaria is discussed in terms of the “chemistry” of the probe-atoms.
35Cl and 79Br NQR Spectra and the Secondary Bonding of Chalcogen Halide Complexes
Authors: Fokina Z. A.
Published: February 2015

The 35Cl and 79Br NQR spectra of chalcogen halide complexes of aluminium, gallium, titanium, zirconium, hafnium, niobium, tantalum, molybdenum, tungsten, rhenium, iron, ruthenium, osmium, iridium, rhodium, platinum, palladium and gold are discussed.

Three structure types of these complexes have been distinguished by X-ray structure analysis: type I with AX2 ligand and [MXn„Am] coordination polyhedron; type II with AX3 ligand and [MXn+m] coordination polyhedron; type III, dimeric complexes with M-X-M bridge (where X = Cl, Br and A = S, Se, Te). The formation of secondary M-X-A or M-X-M bonds is characteristic of most structures. The spectra were interpreted by a Townes. Dailey approximation with allowance for the electronic configuration of the metal, mutual influence of ligands and structure features of complexes. Systematic investigation of a big series of chalcogen halide complexes-analogues allowed the following changes in 35CI and 79Br NQR frequencies on secondary bonding to be established for intraligand halogen atoms: A decrease in frequency for type I complexes and an increase in frequency for type II complexes; for halogen atoms in the coordination polyhedron: a decrease in frequency for p metals and transition metals with d>6, and an increase in frequency for metals with d< 6.
Water Molecular Motion and Hydrogen Bond in Paramagnetic [Cu(H2O)6][PtCl6] as Studied by Single Crystal 2H NMR
Authors: Mizuno Motohiro , Iijima Takahiro , Orii Kengo , Suhara Masahiko
Published: February 2015

The temperature and angular dependences of the 2H NMR spectrum were measured for single crystal [Cu(H2O)6][PtCl6]. (e2Qq/h, η) = (132 kHz, 0.72) were obtained for the D nucleus averaged by the fast 180° flip of the water molecule at 297 K. D1(236 kHz, 0.10) and D2(246 kHz, 0.09) were obtained for two unequal D nuclei of the water molecule at 133 K. Below Tc , at least three nonequivalent waters were found to exist. The jumping rate for the 180° flip of the water molecule (k) was obtained from the simulation of 2H NMR spectra at H0||[111] direction. The activation energy Ea and the jumping rate at infinite temperature were estimated from the temperature dependence of k to be 24kJmol-1 and 1 x 1013s-1
35Cl NQR in Glassy Crystal of 2-chlorothiophene
Authors: Fujimori Hiroki , Asaji Tetsuo
Published: February 2015

Stable crystalline 2-chlorothiophene has two glass transitions at 164 and 186 K. 35CI NQR measurements were carried out between 77 and 200 K. Two NQR signals with full widths of about 100 kHz at half maximum were observed in this temperature range. The spin-lattice relaxation times T1 were measured at the two peak frequencies. The activation energy obtained from the results of the T1 measurements showed a fairly good agreement with those estimated from calorimetric measurements.
Variation of Quadrupole Splitting in Modified Oxyhemoglobin: A Mössbauer Effect Study
Authors: Oshtrakh M. I. , Milder O. B. , Semionkin V. A. , Berkovsky A. L. , Azhigirova M. A. , Vyazova E. P.
Published: February 2015

Human adult hemoglobin modified by both pyridoxal-5'-phosphate and glutaraldehyde in the oxy-form was studied by Mössbauer spectroscopy. Mössbauer spectra were measured at 87 and 295 K (hemoglobin in lyophilized form) and at 87 K (hemoglobin in frozen solution). The values of the quadrupole splitting for modified oxyhemoglobin were found to be lower then those of oxyhemoglobin without modifications in lyophilized form and frozen solution, respectively. The Mössbauer spectra of modified oxyhemoglobin were also analyzed in terms of the heme iron inequivalence in α-and β-subunits of the tetramer. Differences of the tendencies of temperature dependencies of quadrupole splitting for modified and non-modified oxyhemoglobin in lyophilized form were shown.
Impurity Effects on the Local Structure in the Mixed Hexachlorometallate (A2BCl6 : A = K, Rb, B = Sn, Re, and Pb) Studied by the Chlorine NQR
Authors: Seo Y. M. , Song S. K. , Pelz J.
Published: February 2015

Chlorine NQR was studied for the isostructural hexachlorometallate mixed system. The study shows that Isomorphic hexachlorometallate solid solutions exhibit often impurity induced local structural order because of their relatively clear local site symmetry. This is manifested in the formation of a few satellite lines near the original resonance line and results from the random distribution of impurities on the lattice sites of the corresponding counterpart ions. Using the point charge model and a simple binomial function for the occupation probability of the guest ions on the host lattice sites, the position and the line intensity could be determined, the results of which are in good agreement with the NQR-observation. The temperature region of lattice dynamics in the crystal seems to shift in proportion to the impurity content. This fact explains the gradual change of the transition temperature in the mixed crystal between two starting materials.
Halogen NQR and the Phase Transition in CH3Hg-Halide Family
Authors: Pirnat J. , Trontelj Z. , Lužnik J. , Kirin D.
Published: February 2015

The temperature dependence of the 35Cl NQR line and its relaxation has been measured from 77 K to room temperature. The known displacive phase transition near 162 K is reflected in the change of the slope of the temperature dependence of the quadrupole line, but not so in the chlorine or proton relaxation. The results are discussed in view of the proposed structural changes and thermal vibrations.
14N NQR Studies of Impurity Effects on the Local Structure of NaNO2 -based Mixed Systems
Authors: Song S. K. , Park Y. M. , Jung J. K. , Seo Y. M. , Choh S. H.
Published: February 2015

The influence of impurities on the 14N NQR lineshape of Na1-xAgxNO2 and [NaNO2]1-x-[BNO3]x (B = Na, K) at room temperature has been investigated. Carrying out spectral analysis in conjunction with classification of the local field inhomogeneities according to the structurally isomorphic, Na1-xAgxNO2 , and anisomorphic [NaNO2]1-x[BNO3]x systems, enabled an under-standing of the microscopic nature of impurity-induced local disorder. The iso-and anisomorphic systems reveal their own unique features of the impurity induced local disorder. They are charac-terized by a static, random distribution of impurities in the isomorphic system and a fast motion of the impurity-induced mobile point defects in the anisomorphic system. However, for both systems, neither a change of the 14N NQR frequency nor a multisplitting of the lines is observed because of the relatively low symmetry.
Perturbed Angular Correlation Studies in SrTiO3 Single Crystals
Authors: Presa P. de la , Lieb K. P. , Uhrmacher M. , Ziegeler L.
Published: February 2015

The quadrupole hyperfine interactions of 111Cd/111 In probe nuclei in single-crystalline SrTiO3 perovskite samples were investigated using Perturbed Angular Correlation spectroscopy. Three electric field gradients were detected and their fractions and hyperfine parameters were measured in the temperature range from 26 to 700 K. The fraction f0 having a vanishing quadrupole frequency, as expected for 111Cd on substitutional sites in a cubic lattice, starts to develop around 300 K and reaches 100% at 700 K. Two well-defined EFG's having closely lying quadrupole frequencies and asymmetry parameters of ωQi = 49.1(3) Mrad/s, 77, η0= 0.10(2) and ωQ2 = 51.8(3) Mrad/s, η2 = 0.12(2), at room temperature, were identified in the temperature range from 250 to 530 K, and their (100) orientation in the lattice was determined. They are associated with electronic defects at the probe atoms.
Structural Phase Transitions in BaTiO3 Studied via Perturbed Angular Correlations
Authors: Roth J. , Uhrmacher M. , Presa R de la , Ziegeler L. , Lieb K. P.
Published: February 2015

Phase transitions in the ferroelectric perovskite BaTiO3 were studied for 111In-implanted poly-crystalline samples by measuring the electric field gradients by means of Perturbed Angular Correlation spectroscopy. The phase transitions between the orthorhombic ⇔ rhombohedral ⇔ tetragonal ⇔ cubic lattices were investigated in 2 -10 K steps, for increasing and decreasing temperatures, in order to determine their hysteresis. The transition parameters are compared with results from measurements of the spontaneous polarization, electric susceptibility and neutron scattering.
Quadrupole Interaction in Ternary Chalcopyrite Semiconductors: Experiments and Theory
Authors: Dietrich M. , Burchard A. , Degering D. , Deicher M. , Kortus J. , Magerle R. , Möller A. , Samokhvalov V. , Unterricker S. , Vianden R.
Published: February 2015

Electric field gradients have been measured at substitutional lattice sites in ternary semiconductors using Perturbed γ -γ Angular Correlation spectroscopy (PAC). The experimental results for AIBIIIC2 chalcopyrite structure compounds and • AIIB2
IIIC4
IV defect chalcopyrites are compared with ab nitio calculations. The latter were carried out with the WIEN code that uses the Full Potential Linearized Augmented Plane Wave method within a density functional theory. The agreement between experiment and theory is in most cases very good. Furthermore, the anion displacements in AgGaX2 -compounds (X: S, Se, Te) have been determined theoretically by determining the minimum of the total energy of the electrons in an elementary cell.
Charge Distribution Model in Cubic Perovskite-type Compounds
Authors: Alonso R. E. , López-García A.
Published: February 2015

A non-zero electric field gradient tensor, detected by probes that occupy sites with cubic point group symmetry, was observed in many AB03 perovskite-type compounds. This breakdown of local cubic symmetry is commonly associated with the presence of oxygen vacancies around the probe. This effect in BaTixHf1-xO3, with x = 0.7, 0.5, 0.3, 0.1, 0.05 and 0.01 is studied in this work. The cell parameters were obtained at laboratory temperature using XRD spectroscopy. The hyperfine parameters were measured at a 181Ta probe in the B site using Perturbed Angular Correla-tions (PAC) spectroscopy as a function of both temperature and composition. As a common trend, a static asymmetric and distributed quadrupolar interaction, strongly dependent on composition has been observed. The results, together with those corresponding to 1 > x ≥ 0.75, are analyzed using the point-charge model in terms of polarized oxygen vacancies, different covalence of the Ti-0 and Hf-0 bonds with computational simulation for the lattice positions of cations and oxygen vacancies.
Quadrupole Coupling Constants and Mössbauer Isomeric Shifts in Antimony Compounds within Gaussian 98
Authors: Poleshchuk O. Kh. , Latosińska J. N.
Published: February 2015

The electron density and quadrupole coupling constants of molecules containing Sb are analysed. The NQCC for antimony, calculated using the extended basis 6-311G** are much lower than the experimental data, while the use of the small 3-21G* basis led to NQCC closer to the experimental ones.
NMR/NQR Study on Magnetism of Spin Ladder Sr2.5Ca11.5Cu24O41
Authors: Kumagai Ken-ichi , Tsuji Sigenori , Maki Katsuhiko
Published: February 2015

Long-range antiferromagnetic (AF) order in the doped spin ladder compound of Sr2.5Ca11.5Cu24O41 is investigated by heat capacity, magnetization and Cu-NMR/NQR measurements. We suggest that this AF order is primarily responsible for the chain Cu moments
Effect of Intermolecular Hydrogen Bonding on the Nuclear Quadrupole Interaction in Imidazole and its Derivatives as Studied by ab initio Molecular Orbital Calculations
Authors: Nakamura Nobuo , Masui Hirotsugo , Ueda Takahiro
Published: February 2015

Ab initio Hartree-Fock molecular orbital calculations were applied to the crystalline imidazole and its derivatives in order to examine systematically the effect of possible N-H---N type hydrogen bond-ing on the nuclear quadrupole interaction parameters in these materials. The nitrogen quadrupole coupling constant (QCC) and the asymmetry parameter (η) of the electric field gradient (EFG) were found to depend strongly on the size of the molecular clusters, from single molecule, to dimer, trimer and to the infinite molecular chain, i.e., crystalline state, implying that the intermolecular N-H -N hydrogen bond affects significantly the electronic structure of imidazole molecule. A certain correla-tion between the QCC of 14N and the N-H bond distance R was also found and interpreted on the basis of the molecular orbital theory. However, we found that the value of the calculated EFG at the hy-drogen position of the N-H group, or the corresponding QCC value of 2 H, increases drastically as R-3 when R is shorter than about 0.1 nm, due probably to the inapplicability of the Gaussian basis sets to the very short chemical bond as revealed in the actual imidazole derivatives. We suggested that the ob-served N-H distances in imidazole derivatives should be re-examined.
Quadrupolar Relaxation -what would we do without it in High-Tc Superconductor Studies?
Authors: Brinkmann Detlef
Published: February 2015

This paper emphasizes the fact that valuable information on the dynamics of high-Tc super-conductors is concealed in that part of the spin-lattice relaxation which arises from quadrupolar interactions. We briefly discuss the problem how to disentangle magnetic and quadrupolar time dependent interactions if both are present, thus leading to multiexponential magnetization recovery laws. We then discuss two examples from our studies of the high-Tc superconductor YBa2Cu4O8 where the identification of a quadrupolar contribution to the spin-lattice relaxation has been es-sential to draw the relevant conclusions. One example is concerned with the charge fluctuations associated with an electronic crossover showing up in the oxygen relaxation. The second example is dealing with the separation of charge and spin excitations and the validity of the single-spin fluid model.
Specific Heat and Nuclear Quadrupole Resonance Study of Thiourea-Hexachloroethane Inclusion Compound
Authors: Chekhova G. N. , Goren S. D. , Krieger Ju. H. , Linsky D. , Lusternik V. , Panich A. M. , Semenov A. R. , Voronel A.
Published: February 2015

Specific heat and 35Cl nuclear quadrupole resonance (NQR) measurements of the channel thio-urea-hexachloroethane inclusion compound are presented. Experimental NQR data confirm the results of atom-atom potential calculations that the guest sublattice comprises two types of nearly commensurate finite molecular chains, having different structure and separated by domain walls. Specific heat measurements show phase transition near 96 K.
Solid State Effects in 4,6-Dichloropyrimidine Studied by 35Cl-NQR Spectroscopy and ab initio Calculations
Authors: Latosińska J. N. , Kasprzak J.
Published: February 2015

Quantum chemistry methods -ab initio -have been used for the assignment of the 35Cl-NQR resonance frequencies to particular chlorine atoms substituted in positions 4 and 6 of pyrimidine. The so-called solid state effect, that is the influence of intermolecular interactions, in particular hydrogen bond formation, on the NQR parameters has also been studied.
23Na NMR Study of NASICON-type Compounds, Na1+xScxTi2–x(PO4)3
Authors: Masui Hirotsugu , Ueda Takahiro , Miyakubo Keisuke , Eguchi Taro , Nakamura Nobuo
Published: February 2015

The structure of NASICON-type compounds, Na1+xScxTi2-x(PO4)3 (O ≤ x ≤ 2), and the dynamics of Na+ have been investigated by 23Na NMR spectroscopy. It was found that the 23Na 1D and 2D MQMAS spectra depend on the Na concentration, suggesting strongly that the Na+ ions are distributed between two crystallographically nonequivalent sites, one is a special position with axial symmetry, and the other a position of low symmetry. The chemical exchange between these different sites in the crystal takes place at room temperature, which may cause the high Na ion conduction of this material
About Excitation of a Quadrupole Spin Echo
Authors: Zolotaryov I. V. , Kim A. S. , Neufeld P. G.
Published: February 2015

For the first time the excitation of a quadrupole spin echo by a sequence of radio frequency pulses with the filling frequencies ωQ and ωQ ± ΔωQ is theoretically and experimentally considered, where ωQ is the resonance frequency of the raised transition and ΔωQ the offset within the half-width of the NQR line. It is shown that in this case the amplitude of the observable signals does not depend on the offset size, and the echoes appear at times which depend on the intervals between pulses, on the ratio ΔωQ/ωQ, and on the offset sign.
NMR of 93Nb perturbed by Quadrupole Interaction in Quasi-One-Dimensional BaNbS3+d
Authors: Nishihara H. , Kijima N. , Nagata S.
Published: February 2015

Field-swept NMR spectra of 93Nb are examined for a sample of BaNbS2.96 which has a semicon-ductive temperature dependence of the resistivity at low temperature, and a sample of BaNbS3.03 which has a metallic temperature dependence at low temperature. Both spectra are so-called NMR powder patterns perturbed by a quadrupole interaction with a quadrupole frequency υQ = 3e2qQ/2I(2I - l)h of 2.5 [MHz]. No appreciable difference in the spectra has been observed between the two samples, suggesting that the amplitude of the conduction electron density is too small to perturb the electronic environments around the niobium atoms. The general behavior of the nuclear spin-lattice relaxation of 93Nb in both compounds is consistent with an interpretation that the relaxation at low temperature is dominated by a Korringa mechanism and at higher temperature by a quadrupole interaction.
Nature of Hydration Water in (±)-Tris(ethylenediamine)cobalt(III) Chloride Hydrate, (±)-[Co(en)3]Cl3 · nH2O, as Studied by 1H, 2H, and 17O Solid State NMR
Authors: Ueda Takahiro , Nakamura Nobuo
Published: February 2015

The static and dynamics properties of hydration water molecules in (±)-[Co(en)3]Cl3 were studied by means of 1H, 2H, and , 17O solid state NMR. By 'H pulsed field gradient (PFG) NMR the apparent diffusion coefficient of mobile water through a micropore along the crystalline unique c-axis was found to be 1.0 x 10-9 m2 s-1 . The 2H NMR spectrum at 141 K consists of two components, one being a Pake doublet corresponding to a quadrupole coupling constant (QCC) of (226 ± 2) kHz and an asymmetry parameter of the electric field gradient η of 0.08 ± 0.01, and another being a Gaussian line with a linewidth of 3.5 kHz. The 17O NMR spectrum at 300 K also consists of a narrow Gaussian peak and a broad powder pattern with a second order quadrupole effect corresponding to QCC = (6.3 ± 0.5) MHz and η = 0.55±0.02. The broad and narrow components are assigned to water molecules accommodated at general 12g positions and special 2a and 2b positions in the trigonal lattice with space group P1c1. From the ratio of the populations at these positions their potential energy difference was estimated to be between (2.7 ±0.1) and (3.5 ± 0.1) kJmol-1 . The 2H NMR spectrum at room temperature indicates a finite quadrupole interaction which is attributable to the rapid rotation of water molecule about the molecular C2-axis. When the water content exceeds 2.7, the QCC is reduced sharply to (5.0 ±0.1) kHz at 285 K, suggesting that there occurs rapid rotation of water and rapid exchange of 2H between nonequivalent positions.
Special Relativity via Modified Bessel Functions
Authors: Lavenda B. H.
Published: February 2015

The recursive formulas of modified Bessel functions give the relativistic expressions for energy and momentum. Modified Bessel functions are solutions to a continuous time, one-dimensional discrete jump process. The jump process is analyzed from two inertial frames with a relative constant velocity; the average distance of a particle along the chain corresponds to the distance between two observers in the two inertial frames. The recursion relations of modified Bessel functions are compared to the 'k calculus' which uses the radial Doppler effect to derive relativistic kinematics. The Doppler effect predicts that the frequency is a decreasing function of the velocity, and the Planck frequency, which increases with velocity, does not transform like the frequency of a clock. The Lorentz transformation can be interpreted as energy and momentum conservation relations through the addition formula for hyperbolic cosine and sine, respectively. The addition formula for the hyperbolic tangent gives the well-known relativistic formula for the addition of velocities. In the non-relativistic and ultra-relativistic limits the distributions of the particle's position are Gaussian and Poisson, respectively.
Millimeter Wave Spectroscopy of Ne-CO
Authors: Roth D. A. , Pak I. , Surin L. A. , Dumeshb B. S. , Winnewisser G.
Published: February 2015

The pure rotational b-type spectrum of the van der Waals complex Ne-CO has been measured using a pulsed jet, intracavity millimeter wave spectrometer. The millimeter wave generation is based on the OROTRON principle. The high sensitivity of the spectrometer allowed measurements of R(J), K = 1 ← 0 transitions between 108 and 150 GHz of the Ne isotopomers 20 Ne-CO and 22 Ne-CO. This new millimeter wave data set together with the microwave data in the literature, i.e. a-type microwave transitions, yield in a fit to an asymmetric rotor a reliable set of ground state constants. These are for 20 Ne-CO: A = 107127.021(14) MHz, B = 3479.6597(95) MHz, and C = 3039.5387(93) MHz. For both 20 Ne-CO and 22 Ne-CO, a global fit to a near-symmetric rotor was performed, taking into account the infrared and microwave transition frequencies from the literature and the millimeter wave measurements of the present work.
Phase Transitions and Water Dynamics of [Mn(H2O)6](ClO4 )2 Studied by Differential Scanning Calorimetry and Neutron Scattering Methods
Authors: Mikuli E. , Migdał-Mikuli A. , Natkaniec I. , Mayer J.
Published: February 2015

DSC measurements performed at 95 -290 K have shown that [Mn(H 2 O) 6 ](CIO 4) 2 possesses, besides a high-temperature phase, existing above 323 K, four low-temperature solid phases. The inelastic incoherent neutron scattering (IINS) spectra and neutron powder diffraction (NPD) pat-terns registered at 20 -290 K have supported the DSC results and provided evidence that the investigated substance possesses even more than five solid phases. The IINS spectra have shown that in the room-temperature phase, water molecules perform fast stochastic reorientation at the picosecond scale. The orientational disorder characteristic for the room-temperature phase can be easily overcooled and frozen. Even by relatively slow cooling at ca. 40 K/hour a metastable, orientational (protonic) glass phase is formed below ca. 160 K. Below ca. 100 K, a structural phase transition was observed by the NPD, however the IINS spectra indicate existence of the pure ordered low-temperature phase only after annealing the sample for a few hours at 100 K. On heating, a structural phase transition takes place at ca. 120 K, and at ca. 225 K water molecules begin fast reorientation.
Crystal Structure of Trimethylammonium Tetrafluoroborate in Three Solid Phases
Authors: Ishida Hiroyuki , Kashino Setsuo , Ikeda Ryuichi
Published: February 2015

The crystal structure of (CH3)3 NHBF 4 was studied in three solid phases by X-ray diffraction techniques. The structures of the ionic plastic phase (Phase I) stable above 453 K and Phase II between 384 and 453 K are CsCl-type cubic (a = 5.772(4) Å) and tetragonal (a = 9.815(5) and c = 6.895(5) Å), respectively. The room temperature phase (Phase III) forms a monoclinic lattice (space group P21/m, a = 5.7017(8), b = 8.5724(9), c = 7.444(1) Å, and ß = 102.76(1)°). BF4
− ions in this phase were shown to be disordered in four orientations.
Structural Studies of N-(2,4,6-trisubstitutedphenyl)-Chloroacetamides, 2,4,6-X3C6 H2 -NHCO-CH3_y Cly, (X = CH3 or Cl and y = 1 -3)
Authors: Gowda B. Thimme , Svoboda I. , Fuess Hartmut
Published: February 2015

The effect of side chain and ring substitutions on the crystal structures of N-(2,4,6-substitutedpheny)- chloroacetamides of the type, 2,4,6-X3C6H2-NHCO-CH3_yCly (X = CH3 or Cl and 1 ⩽ y ⩽ 3), has been studied by determining the crystal structures of N-(2,4,6-trimethylphenyl)- 2-chloroacetamide, 2,4,6-(CH3)3C6H2-NHCO-CH2Cl (TMPMCA); N-(2,4,6-trichlorophenyl)-2- chloroacetamide, 2,4,6-Cl3C6H2-NHCO-CH2Cl (TCPMCA); N-(2,4,6-trichlorophenyl)-2,2-dichloroacetamide, 2,4,6-Cl3C6H2-NHCO-CHCl2 (TCPDCA) and N-(2,4,6-trichlorophenyl)-2,2,2- trichloroacetamide, 2,4,6-Cl3C6H2-NHCO-CCl3 (TCPTCA). The crystal type, space group, formula units and lattice constants in A are: (TMiPMCA); monoclinic, P21,/n, Z = 8, a = 9.029(5), b = 15.688(2), c = 16.150(3), ß = 96.77(2)°; (TCPMCA): orthorhombic, Pna21, Z = 8, a = 30.708(4), b = 4.685(1), c = 14.506(2); (TCPDCA) orthorhombic, P212121 Z = 4, a = 16.459(3), b = 15.240(3), c = 4.640(1) and (TCPTCA): triclinic, P Ī , Z = 4, a = 9.828(2), b = 11.953(2), c = 12.278(2), a = 71,05( 1)°, ß = 75.26(2)°, g = 83.29( 1)°. The results have been analysed along with the structures of the ring unsubstituted N-phenylacetamide (PA), N-phenyl-2,2,2-trichloro-acetamide, side chain unsubstituted N-(2,4,6-trichlorophenyl)-acetamide, 2,4,6-Cl3C6H2-NHCO-CH3 (TCPA) and the corresponding di-substituted phenyl acetamides and chloroacetamides. The compounds TMPMCA, TCPMCA and TCPTCA have 2 molecules each in their asymmetric units. This is in agreement with the multiple lines observed in the 35CI NQR spectra of TCPTCA. Further, this compound shows disorder as indicated by the multiplicity of the C(side chain) - Cl bonds. The compound TCPMCA does not show 35C1 NQR spectra, while the compound TMPMCA shows a single frequency which fades out above 200 K, indicating that it may undergo a phase transition well below room temperature. Conversion of 2,4,6-trichloroaniline into 2,4,6-trichlorophenyl acetamide and gradual replacement of H-atoms in the side chain of the latter decreases slightly the mean ring distances of the compounds, while the replacement of the 3 Cl by 3 CH3 groups in the ring increases it's mean distance. Changes in the mean ring distances are smaller as the effect has to be transmitted through the peptide linkage. The molecules in compounds TCPDCA and TCPTCA are linked in chains by -NH-O- hydrogen bonds (about 3 Å) between the amide groups of the molecules.
35CI NQR and Structural Studies of N-(2,6-Dichlorophenyl)-Amides, 2,6-Cl2C6H3-NHCO-R (R = H or CH3-y Xy and X = CH3 or CI; y = 0,1, 2 or 3)
Authors: Gowda B. Thimme , Paulus Helmut , Fuess Hartmut
Published: February 2015

The effect of side chain substitution on the 35CI NQR and crystal structure of amides of the type N-(2,6-dichlorophenyl)-amides, 2,6-Cl2C6H3-NHCO-R (R = H or CH3_yXy where X = CH3 or CI and y = 0, 1, 2 or 3), has been studied by measuring the 35C1 NQR spectra and determining the crystal structures of the compounds N-(2,6-dichlorophenyl)-formamide, 2,6-Cl2C6H3- NHCO-H (DCPFA); N-(2,6-dichlorophenyl)-2-methylacetamide(propionamide), 2,6-Cl2C6H3- NHCO-CH2CH3 (DCPMA); N-(2,6-dichlorophenyl)-2,2-dimethylacetamide(isobutyramide), 2,6- Cl2C6H3-NHCO-CH(CH3 ) 2 (DCPDMA) and N-(2,6-dichlorophenyl)-2,2,2-trimethylacetamide (neopentylamide), 2,6-Cl2C6H3-NHCO-C(CH3)3 (DCPTMA), and by analysing the present data along with the 35CI NQR spectra and / or crystal structures of the compounds, 2,6-dichloroaniline, 2,6-Cl2C6H3-NH2 (DCA), N-(2,6-dichlorophenyl)-acetamide, 2,6-Cl2C6H3--NHCO-CH3 (DCPA), N-(2,6-dichlorophenyl)-2-chloroacetamide, 2,6-Cl2C6H3-NHCO-CH2Cl (DCPCA), N- (2,6-dichlorophenyl)-2,2-dichloroacetamide, 2,6-Cl2C6H3-NHCO-CHCl2 (DCPDCA) and N- (2,6-dichlorophenyl)-2,2,2-trichloroacetamide, 2,6-Cl2C6H3-NHCO-CCl3 (DCPTCA). The crystal type, space group, formula units and lattice constants in A of the new structures are;DCPFA: orthorhombic, Pbca, Z = 8, a = 8.593(3), b = 12.728(4), c = 14.376(4); DCPMA: orthorhombic, P212121, Z = 4, a = 4.774(2), b = 10.961(5), c = 19.562(8); DCPDMA: monoclinic, P21/c, Z = 4, a = 9.901(4), b = 13.785(5), c = 9.060(3), ß = 103.58(2)° and DCPTMA: monoclinic, P21/n, Z = 8, a = 16.047(5), b = 9.882(3), c = 16.270(5) ß = 102.12(1)°. The compound, DCPTMA shows two molecules in its asymmetric unit. This is in agreement with the multiple lines observed in the 35CI NQR spectra of the compound. The conversion of DCA (monoclinic) into it's various acid amides DCPFA, DCPA, DCPMA, DCPDMA, DCPTMA, DCPCA and DCPTCA affects it's crystal symmetry. The replacement of the side chain CH3 in DCPA by the H atom or substitution of either a CH3 group or a CI atom for one of the H atoms in the side chain CH3 or replacement of the two ring CI atoms by the H atoms changes it's crystal symmetry from monoclinic to orthorhombic, while the substitution of 2 or all the 3 H atoms in the CH3 group of DCPA by 2 or 3 CH3 groups or CI atoms restores it's crystal symmetry back to the monoclinic type. The bond lengths and bond angles are normal except for some deviations.
Pseudo-symmetries of the Phases of (Et4N)2ZnBr4
Authors: Sondergeld P. , Fuess H. , Mason S. A. , Ishihara H. , Schmahl W. W.
Published: February 2015

The phase sequence of (Et4N)2ZnBr4 has been determined based on thermal analysis. Below the decomposition point (572 K) four phases are distinguished. The structures of three of the phases have been determined from 4-circle diffraction data at 240 (neu-trons), 299 and 373 K (X-rays), respectively. The multiply twinned low-temperature phase (at 240 K) is characterized by a pseudo-orthorhombic lattice (monoclinic, Plal, a = 17.6120(9] Å, b = 8.8195(4) Å, c = 16.1062(6) Å and ß=89.94(2)°), whereas the room-temperature phase (299 K:P421c, a = 8.9874(6)Åand c = 15.9774 Å) and the first high-temperature phase (373 K: P42 /nmc, a= 9.145(4) Å and c = 15.835(8) Å) belong to the tetragonal crystal system. The transitions between the three phases are essen-tially connected with a stepwise ordering of the Et4N+ ions, whereas the positions of the heavy atoms change only slightly. Three 81Br NQR lines are observed between 77 and 204 K.
Static and Dynamic Dielectric Polarization and Viscosity of n-Hexylcyanobiphenyl in the Isotropic and Nematic Phases
Authors: Jadżyn Jan , Czechowski Grzegorz , Bauman Danuta
Published: February 2015

On the basis of the temperature dependence of the static principal permittivities, £y and e x , measured for the nematic phase of «-hexylcyanobiphenyl (C6H13 -Ph-Ph-C=N, 6CB), a value of the angle ß between the long molecular axis and the direction of the dipole moment /µ of 6CB, as well as the order parameter S(T), were obtained by use of the Maier-Meier equations. From the dielectric relaxation and viscosity data, the contribution of the nematic potential to the molecular dynamics was estimated. In the isotropic phase the dielectric and viscosity data allow one, in the framework of the Debye model, to estimate the effective length of 6CB molecule.
Nonlinear Stability of a Cylindrical Interface with Mass and Heat Transfer
Authors: Lee Doo-Sung
Published: February 2015

The nonlinear Rayleigh-Taylor stability of a cylindrical interface between vapor and the liquid phases of a fluid is studied when the phases are enclosed between two cylindrical surfaces coaxial with the interface, and when there is mass and heat transfer across the interface. The method of multiple time scale expansion is used for the investigation. A simple nondimensional parameter is found to characterize the stability of the system. Using this parameter, the region of stability is displayed graphically.
Comment on the Paper "Non-kinematicity of the Dilation-of-time Relation of Einstein for Time-intervals" by S. Golden
Authors: Schäfer G.
Published: February 2015

In a recent paper [1] S. Golden is trying an interpretation of Einstein's theory of special relativity solely based on the propagation of light-pulses which aims at circumventing the problems scientists sometimes do have with the "twin paradox", i.e. with the physical reality of the kinematical dilation-of-time. However it is well known that propagation of light does not cover the whole structure of relativistic spacetime because of the conformal invariance of the Maxwell equations. Thus the paper [1] is fundamentally incomplete in its applied physical tools. In my comment it will be shown that the title of the paper is a misconception and that another aspect in the paper is false too. If S. Golden would have treated in the paper not only light-pulses but also decaying systems the shortcomings would not have occurred. The sole tool of the author for relating inertial systems is the exchange of light-pulses (including reflections) between two inertial systems, called A-system and B-system, with time coordinates t and r, respectively. The light-pulses are propagating either into the direction of the inertial-systems relative velocity or into the opposite direction. No doubt, the ratio At/AT of the time-intervals between fixed-position (origins of the systems) passage-times of the same two light-pulses in the A-system and in the B-system is given by, combine the Eqs. (6) and (12) in the paper in question,
Locality or Non-Locality in Quantum Mechanics: Hidden Variables without "Spooky Action-at-a-Distance"
Authors: Aharonov Yakir , Botero Alonso , Scully Marian
Published: February 2015

The folklore notion of the "Non-Locality of Quantum Mechanics" is examined from the point of view of hidden-variables theories according to Belinfante's classification in his Survey of Hidden Variables Theories. It is here shown that in the case of EPR, there exist hidden variables theories that successfully reproduce quantum-mechanical predictions, but which are explicitly local. Since such theories do not fall into Belinfante's classification, we propose an expanded classification which includes similar theories, which we term as theories of the "third" kind. Causal implications of such theories are explored. -Pacs: 03.65.Bz
The Mean King's Problem: Spin
Authors: Aharonov Yakir , Englert Berthold-Georg
Published: February 2015

We show how one can ascertain the values of four mutually complementary observables of a spin-1 degree of freedom. -Pacs: 03.65.Bz
Verifying Atom Entanglement Schemes by Testing Bell's Inequality
Authors: Angelakis Dimitris G. , Beigea Almut , Knight Peter L. , Munro William J. , Tregenn Ben
Published: February 2015

Recent experiments to test B ell's inequality using entangled photons and ions aimed at tests of basic quantum mechanical principles. Interesting results have been obtained and many loopholes could be closed. In this paper we want to point out that tests of Bell's inequality also play an important role in verifying atom entanglement schemes. We describe as an example a scheme to prepare arbitrary entangled states of N two-level atoms using a leaky optical cavity and a scheme to entangle atoms inside a photonic crystal. During the state preparation no photons are emitted, and observing a violation of B ell's inequality is the only way to test whether a scheme works with a high precision or not.
Spin Squeezing in Degenerate and Non-degenerate Atomic Vapors: Some Approaches to Atomic Entanglement
Authors: Bigelow Nicholas P.
Published: February 2015

In this paper we discuss our recent work on the creation of spin-squeezed states in both thermal (room temperature) gasses and in spinor Bose-Einstein condensates.
Unusual Bound or Localized States
Authors: Cirone M. A. , Metikas G. , Schleicha W. P.
Published: February 2015

We summarize unusual bound or localized states in quantum mechanics. Our guide through these intriguing phenomena is the classical physics of the upside-down pendulum, taking advantage of the analogy between the corresponding Newton’s equation of motion and the time independent Schrödinger equation. We discuss the zero-energy ground state in a three-dimensional, spatially oscillating, potential. Moreover, we focus on the effect of the attractive quantum anti-centrifugal potential that only occurs in a two-dimensional situation.
Multiparticle Quantum Superposition and Stimulated Entanglement by Parity Selective Amplification of Entangled States
Authors: Martini Francesco De , Giuseppe Giovanni Di
Published: February 2015

A multiparticle quantum superposition state has been generated by a novel phase-selective parametric amplifier of an entangled two-photon state. This realization is expected to open a new field of investigations on the persistence of the validity of the standard quantum theory for systems of increasing complexity, in a quasi decoherence-free environment. Because of its nonlocal structure the new system is expected to play a relevant role in the modem endeavor on quantum information and in the basic physics of entanglement. - Pacs: 03.65.Bz, 03.67.-a, 42.50.Ar, 89.70.+C
The Inconsistency of the Usual Galilean Transformation in Quantum Mechanics and How To Fix It
Authors: Greenberger Daniel M.
Published: February 2015

It is shown that the generally accepted statement that one cannot superpose states of different mass in non-relativistic quantum mechanics is inconsistent. It is pointed out that the extra phase induced in a moving system, which was previously thought to be unphysical, is merely the non-relativistic residue of the "twin-paradox" effect. In general, there are phase effects due to proper time differences between moving frames that do not vanish non-relativistically. There are also effects due to the equivalence of mass and energy in this limit. The remedy is to include both proper time and rest energy non-relativis-tically. This means generalizing the meaning of proper time beyond its classical meaning, and introduc­ ing the mass as its conjugate momentum. The result is an uncertainty principle between proper time and mass that is very general, and an integral role for both concepts as operators in non-relativistic physics.
Entanglement Capability of Two-qubit Operations
Authors: Kraus B. , Dür W. , Vidal G. , Cirac J. I. , Lewenstein M. , Linden N. , Popescu S.
Published: February 2015

We study the optimal way of creating bi-partite entanglement using a general two-qubit in­ teraction. On the one hand, we analyze the entanglement capability of an arbitrary non-local Hamiltonian acting on two qubits. We explicitly calculate the state which maximizes the entangle­ ment produced per time step 81 during the non-local evolution. On the other hand, we determine the maximal amount of entanglement which can be produced by an arbitrary two-qubit gate. We also give the separable state which leads to the output state containing this amount of entanglement. Furthermore, we consider the situation where auxiliary systems are present. Finally, we determine the non-unitary processes which are able to create entanglement from an initially separable state of two systems.
A Cavity QED Source for Entangled Photons
Authors: Vitali David , Ciaramicoli Giacomo , Tombesi Paolo
Published: February 2015

We study the possible limitations and sources of decoherence of a scheme for the deterministic generation of polarization-entangled photons based on an appropriately driven single atom trapped within an optical cavity. -Pacs: 03.67.Hk, 42.50.Gy, 32.80.Qk
Generation and Detection of Fock-States of the Radiation Field
Authors: Walther Herbert
Published: February 2015

In this paper we give a survey of our experiments performed with the micromaser on the generation of Fock states. Three methods can be used for this purpose: the trapping states leading to Fock states in a continuous wave operation, state reduction of a pulsed pumping beam, and finally using a pulsed pumping beam to produce Fock states on demand where trapping states stabilize the photon number.
Bell States, Bell Operators, and Total Teleportation
Authors: DelRe E. , Crosignani B. , Porto P. Di
Published: February 2015

We identify the operators and the corresponding physical quantities whose measurement allows in principle to obtain total teleportation of the unknown spin state of a single electron. We introduce an analogous scheme for a single photon and discuss its experimental implementation.
Quantum Criticality
Authors: Drummond P. D. , Chaturvedi S. , Dechoum K. , Comey J.
Published: February 2015

We investigate the theory of quantum fluctuations in non-equilibrium systems having large crit­ical fluctuations. This allows us to treat the limits imposed by nonlinearities to quantum squeezing and noise reduction, and also to envisage future tests of quantum theory in regions of macroscopic quantum fluctuations. A long-term objective of this research is to identify suitable physical sys­tems in which macroscopic 'Schrödinger cat'-like behaviour may be observed. We investigate two systems in particular of much current experimental interest, namely the degenerate parametric oscillator near threshold, and the evaporatively cooled (BEC). We compare the results obtained in the positive-P representation, as a fully quantum mechanical calculation, with the truncated Wigner phase space equation, also known as semi-classical theory. We show when these results agree and differ in calculations taken beyond the linearized approximation. In the region where the largest quantum fluctuations and Schrödinger cat-like behaviour might be expected, we find that the quantum predictions correspond very closely to the semi-classical theory. Nature abhors observing a Schrödinger cat. -Pacs: 03.65.Bz