Linewidth Data Research Articles

The distance to the Coma cluster using the B-band Tully-Fisher relation

view Abstract Citations (48) References (60) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Distance to the Coma Cluster Using the B-Band Tully-Fisher Relation Fukugita, M. ; Okamura, S. ; Tarusawa, K. ; Rood, H. J. ; Williams, B. A. Abstract The distance to the Coma cluster was estimated using the B-band Tully- Fisher relation. We took all galaxies for which H I line width data are available in a circle of 4^deg^ radius centered on the Coma cluster, and carried out photographic surface photometry on them. The sample represents a substantial fraction of all spiral galaxies for m_z_< 15.5 mag inside this circle. We estimated carefully possible errors which would enter in each step to form the Tully-Fisher relation. In particular, a detailed estimate was made of the cluster population incompleteness bias for the distance estimation. We found that the correction for the sample incompleteness, when combined with the dispersion of the Tully-Fisher relation, increases the distance modulus by 0.3 mag, but that it cannot be as large as the value recently suspected by Kraan-Kortweg, Cameron and Tammann. As our best estimate for the Coma cluster we obtained the distance modulus of (m - M)^0^= 34.5 +/- 0.4, which corresponds to a Hubble constant H_0_ = 92^+21^_-17_km s^-1^ Mpc^-1^. Publication: The Astrophysical Journal Pub Date: July 1991 DOI: 10.1086/170250 Bibcode: 1991ApJ...376....8F Keywords: Astronomical Photometry; Distance; Galactic Clusters; Galactic Radiation; Radio Astronomy; Radio Sources (Astronomy); Calibrating; Correction; Cosmology; H Lines; Spectral Line Width; Astrophysics; COSMOLOGY; GALAXIES: CLUSTERING; GALAXIES: DISTANCES; GALAXIES: PHOTOMETRY; RADIO SOURCES: 21 CM RADIATION full text sources ADS | data products SIMBAD (63) NED (62)

High‐field magnetic resonance studies oftert‐butanol in liquid and solid phases

Abstract1H and13C line widths and1H,2H,13C and17O spin–lattice relaxation (times (T1) oftert‐butanol (TB) were studied at a field strength of 9.4 T in the liquid and solid states (160–299 K). The NMR line width data reveal the existence of at least two crystalline forms between 160 K and the metling point (299 K). The ordered phase (solid II) is observed throughout the whole temperature region on warming, indicating that the disordered phase (solid I), observed betweenca. 210 K and the melting point, is monotropic. The line narrowing of the1H resonances for solid I, observed around 225 and 280 K, is ascribed to the onset of overall molecular tumbling and translational diffusion, respectively. The1H line width of solid II is constant between 160 and 284 K. Activation parameters for the overall molecular tumbling and/or internal methyl andtert‐butyl reorientations were obtained from theT1data. The long correlation time (75–92 ps at the melting point) and high activation energy (27–37 kJ mol−1) suggest that the overall tumbling in the disordered and liquid phases involves hydrogen‐bonded aggregates. The dynamics of the methyl group, in contrast to thetert‐butyl group, appear to be only slightly affected by change of state and phase (activation energy 11–12 kJ mol−1).

Thermal and nonthermal motions in dense cores

Kinetic temperature and NH3 line width data for 61 dense cores with embedded IRAS sources show that the nonthermal component of the core motions increases with source luminosity more rapidly than does the thermal component. The trends cross in the luminosity range 7-22 solar luminosities, which divides the regimes of thermal and nonthermal motions. Maps of line widths in dense cores and their surrounding clouds indicate that nonthermal line broadening is due not only to stellar winds, but also to gas properties independent of the star. The 'initial conditions' for motions in cores forming lower-mass stars are primarily thermal, while those in cores forming higher mass stars are probably primarily nonthermal. These differences in core properties may arise from differences in the relative proportion of magnetic and gravitational energy in the condensing core. 30 refs.

NMR linewidth study of a latex interpenetrating network

Polymer structure developed in latex particles has been investigated by measuring the temperature dependence of the carbon magnetic resonance (CMR) peak linewidths. Interpenetrating polymer networks (IPN) were formed by a continuous-addition emulsion polymerization process, in which a crosslinked seed particle was the site for formation of a linear second-stage polymer. Morphology was controlled by the level of crosslinking in the seed stage. The two polymers of the composite particle differ in their glass-transition temperatures by 100°C. By heating the particles to 50°C above the glass-transition temperature of the softer polymer, which formed the continuous network phase of this composite, it was possible to observe its CMR spectrum independently of the other polymer. The temperature dependence of the linewidth varied with the structure of the network. This was characterized by limiting linewidth behavior at both low and high temperature, which systematically varied as a function of the degree of mixing the two phases. Differential scanning calorimetry and electron microscopy corroborated the morphology change observed with the linewidth data. The influence of a diluent, present during formation of the network stage, was also examined with this CMR approach.

Optical properties of high-quality InGaAs/InAlAs multiple quantum wells

We have measured the narrowest half-width at half-maximum photoluminescence linewidth of 2.8 meV, in 40-period lattice-matched In0.53Ga0.47As/In0.52Al0.48As multiple quantum wells, grown by molecular-beam epitaxy with growth interruption. A simple analysis of the linewidth suggests that the structure has near perfect interfaces. Temperature-dependent photoluminescence linewidth data indicate impurity incorporation due to the growth interruption. However, the high quality of the multiple quantum well is not impaired as is seen in the room-temperature absorption data, where excitonic features up to n=3 sublevel are clearly seen. Carrier lifetime in this multiple-quantum-well system has been measured, we believe for the first time, using the picosecond photoluminescence correlation technique. A lifetime of 860 ps is obtained, which is similar to the value obtained for high-quality GaAs/AlGaAs and In0.53Ga0.47As/InP quantum wells. This further confirms the high quality obtained in this ternary material system using growth interruption.

Determination of the internal stress distribution parameters alpha and beta for Fe3+-doped yttrium aluminium garnet crystals from the electron paramagnetic resonance linewidth and spin-lattice coupling coefficients

In this paper the spin-lattice coupling coefficients G11 and G44 for Fe3+ ions, in both octahedral and tetrahedral sites of YAG crystals, have been calculated within the framework of the cubic field approximation from the author's simple and uniform method of calculating these coefficients in two cubic (Oh and Td) symmetries, by using the parameters obtained from the optical spectra. The results can satisfactorily explain the uniaxial-stress EPR experiments for the two sites and are reasonable. On this basis, the parameters alpha and beta that characterize the distributions of internal stresses and strains are determined for the two sites from the distinctive linewidth data of EPR spectra. It appears that this method can be used to study the internal stress distributions for the crystals containing paramagnetic ions, particularly in the absence of experimental data of spin-lattice coupling coefficients.

Neutron quasielastic scattering results for Me(NH 3) 6(XY 4) 2, Me(NH 3) 6(XY 3) 2 and Me(NH 3) 6X 2 compounds, compared with the calorimetric and Raman line width data — a new analysis

Quasielastic neutron scattering data for Ni(NH 3) 6(CIO 4) 2, Mg(NH 3) 6(BF 4) 2, Ni(NH 3) 6(NO 3) 2, Mg(NH 3) 6(NO 3) 2, Ni(NH 3) 6Cl 2 and Ni(NH 3) 6Br 2 were subjected to a new analysis in which not only the correlation times for NH 3 uniaxial reorientations but also a new parameter “excess elasticity” were determined. The new parameter gave us information concerning anharmonic librations of the NH 3 groups. All neutron data were compared with the calorimeter and Raman line width data. An attempt to ascribe the phase transformations to transitions from hindered to free reorientations of the NH 3 groups or/and the anions was made.

19F NMR studies in ABF4-type layered antiferromagnets.

$^{19}\mathrm{F}$ NMR studies of polycrystalline ${\mathrm{NH}}_{4}$${\mathrm{FeF}}_{4}$, ${\mathrm{RbFeF}}_{4}$, and ${\mathrm{KFeF}}_{4}$ in the paramagnetic phase reveal the existence of two distinct types of fluorine sites. From the line-shift measurements together with the available magnetic susceptibility data, the value for the transferred hyperfine coupling between the fluorine nuclear spin and the neighboring iron electron spin has been derived. The values of the hyperfine tensor components indicate the almost isotropic nature of the Fe-F bond in the three compounds. Furthermore, the hyperfine fields at both types of fluorine sites are found to be almost temperature independent in the paramagnetic phase, which is in agreement with the susceptibility behavior of these compounds. Thus apparently no difference is reflected in the behavior of the time-averaged local properties as a function of temperature among the three compounds. However, an essentially different behavior of the linewidth with temperature of the fluorine atoms [(F(1)] bonded with one iron neighbor and fluorine atoms [F(2)] bonded with two iron neighbors is observed. In all the compounds the resonance lines for both types of fluorines are broadened anomalously below certain temperatures and finally both the lines disappear at ${\mathit{T}}_{\mathit{N}}$. Although the transition temperatures (${\mathit{T}}_{\mathit{N}}$) of the three compounds are very close among themselves (${\mathit{T}}_{\mathit{N}}$ lie in the range 133.5--136 K), the anomalous line broadening appears in widely different temperature regions.These results are compared with those reported earlier for ${\mathrm{CsFeF}}_{4}$. Moreover, an attempt has been made to correlate the temperature-dependent linewidth of the F(1) line with the effect of a critical slowing down of the fluctuations of the electronic spins of the ${\mathrm{Fe}}^{3+}$ ion with a lowering of the temperature. The temperature-dependent linewidth \ensuremath{\delta}${\mathit{H}}_{1}$(T) is found to fit well with the relation \ensuremath{\delta}${\mathit{H}}_{1}$(T)\ensuremath{\propto}${\mathrm{\ensuremath{\epsilon}}}^{\mathrm{\ensuremath{-}}\mathit{w}}$ in the critical regions, where \ensuremath{\epsilon}=(T-${\mathit{T}}_{\mathit{N}}$)/${\mathit{T}}_{\mathit{N}}$ is the reduced temperature. The exponent w involves, besides two static exponents \ensuremath{\gamma} and \ensuremath{\nu}, the dynamic exponent z and is related by w=-\ensuremath{\gamma}+\ensuremath{\nu}(d-z). A comparison of the values of w with that predicted by the current theory of critical dynamics indicates that the magnetic interactions in ${\mathrm{NH}}_{4}$${\mathrm{FeF}}_{4}$, ${\mathrm{RbFeF}}_{4}$, and ${\mathrm{CsFeF}}_{4}$ are three dimensional in nature, whereas in ${\mathrm{KFeF}}_{4}$ the two-dimensional (2D) interactions are predominant. Nevertheless, the presence of a broad critical region even in each of the first three systems as observed from the linewidth data indicates that the 2D interactions are still present there.

Evaluation of the parameters that characterize the distributions of internal stresses in YAG: Cr 3+ crystals from the data of EPR linewidth

The spin-lattice coupling coefficients C 11 and C 44 for Cr 3+ ions in various doped YAG crystals have been calculated within the framework of cubic field approximation from a uniform and simple method of calculating the spin-lattice coupling coefficients G 11 and G 44 and from the elastic constants c ij of YAG crystal. On this basis, the parameters α and β which characterize the random distributions of internal stresses and strains are determined from the linewidth data of EPR spectra. It appears that the theoretical method of calculating the coefficients G 11 and G 44 for d n ions in cubic crystals can be, in some cases, used to study the distributions of internal stresses and strains in crystals.

Stimulated Raman probing of supercooling and phase transitions in large N2 clusters formed in free jet expansions

High resolution stimulated Raman spectroscopy (SRS) has been used to examine N2 and N2/He free jet expansions and also equilibrium samples of N2 from 15 to 110 K. The jet spectra show the formation of large liquid clusters which supercool and subsequently freeze to form crystalline β-N2 solid and, in He expansions, undergo a further transformation to a partially annealed α-N2 form. CW-SRS frequency and linewidth data obtained for equilibrium samples of the condensed phases of N2 yielded frequency–temperature relations used in deducing internal temperatures for the clusters produced in the expansion experiments. Analysis of the cooling curves indicates a mean cluster diameter of 35 nm and favors a prompt freezing process rather than a gradual conversion of liquid to solid in a single cluster on the microsecond time scale of the experiments. Supercooling limits of 34 to 44 K are deduced for the liquid, far below the triple point temperature of 63.2 K at which equilibrium samples freeze. Some evidence for surface versus bulk contributions to the spectra is seen in the asymmetric line shapes observed for liquid clusters in the condensation region. The results show that the high spectral and spatial resolution of nonlinear Raman methods such as SRS and CARS provide a unique probe of the condensation processes in free jet expansions.

Sulphur‐33 and oxygen‐17 NMR studies of sulpholane in acetic acid and related solvents

AbstractSulphur‐33 NMR spectra were obtained for sulpholane in acetic acid, trifluoroacetic acid, methyl acetate and methyl trifluoroacetate over the entire solution range and at a variety of temperatures. Oxygen‐17 NMR spectra were recorded for both components of each solution. The line width and chemical shift data are discussed in terms of molecular interactions and viscosity variations. Some variable‐temperature measurements are included, as are some values of 13C spin‐lattice relaxation times. It is concluded that there is an interaction, probably protonation, between sulpholane and trifluoroacetic acid, although occurring to only a small extent, which is not shown by the other solutions. The 33S and 17O line widths of sulpholane are peculiarly sensitive to the interaction.

Conformational isomerism in a series of alkylpiperazonium derivatives investigated by high field 1H and 13C NMR spectroscopy

Changes in the 1H and 13C NMR spectra over the temperature range −30 to +60°C are used to investigate conformational isomerism in N,N′-dimethylpiperazine, the N,N,N′,N′-tetramethylpiperazonium dication and trialkylpiperazonium monocations of the type MeN(CH2CH2)2N(Me)R+, where R = Me, Et, n-Pr, i-Pr or CH2X (X = Cl, Br or I). Measurements of the rate of ring inverson of the heterocyclic cations (1–4) from line width data yield values of the enthalpy and entropy of activation; ΔH≠ = 64 to 75 ± 2 kJ mol−1 and ΔS≠ = 30 to 80 ± 10 J K−1 mol−1. These are compared with the values derived from the activation energy (ΔG≠ = 47 to 56 ± 1 kJ mol−1) obtained from the coalescence temperatures of NMR signals from appropriate sets of indicating nuclei. The related seven-membered heterocycle N,N,N′,N′-tetramethylhomopiperazonium dication (2) exhibits a higher barrier to ring inversion than those of the alkylpiperazonium derivatives. For the N,N,N′-trialkylpiperazonium ions (4–7) with unlike substituents on the quaternary nitrogen, the NMR spectra show that 70–75% of the ground state molecules have the bulkier group in the equatorial situation. Also reported are some 14N coupling constants, 1J(14N, 13C) of 2.5–4.0 Hz, and 3J(14N, 1H) of 1.5–2.0 Hz, involving nitrogen atoms of the quaternary centres.

COMMENT ON THE STUDY OF ASPHALTENES BY X-RAY DIFFRACTION

Abstract In the x-ray diffraction of carbonaceous materials, there is no logical reason to assume an interrelation between the intensity of the (002) peak, reflecting intermolecular “stacking” order of aromatic planes, and the fractional aromaticity fa measured by carbon nuclear magnetic resonance. Approaches to the calculation of a diffraction-based aromaticity f002 by comparing the intensity of the (002) peak to that of the γ-band at 450 pm, reflecting intermolecular order of saturated chain hydrocarbons, are fundamentally flawed. The use of diffraction linewidth data for peaks near 210 pm (“(100)”) and near 120 pm (“(110)”) to infer an aromatic diameter has difficulties in systems containing hydroaromatic molecules (e.g., tetralin) because the naphthenic moiety contributes to diffraction peaks in the 210 and 120 pm regions.

Investigations concerning the potential for using 1h nmr relaxometry or high‐resolution spectroscopy of plasma as a screening test for malignant lung disease

In 158 plasma samples, obtained from patients with lung carcinoma, lung metastases, and infectious or inflammatory lung diseases and from healthy controls, the NMR relaxation times T1 and T2 of water protons were measured at a resonance frequency of 20 MHz by pulsed NMR techniques and adjusted to a standardized total plasma protein concentration. For one-third of these samples water-suppressed 500-MHz 1H NMR spectroscopy at 37 degrees C was used (a) to determine the widths of the composite lipid methyl and methylene signals, and (b) to quantitate individual lipid methylene signal components that could be detected in resolution-enhanced spectra. In addition, hematological parameters and the plasma levels of several acute phase proteins and apolipoprotein-A were monitored. No diagnostically significant differences between lung carcinoma patients and patients with nonmalignant lung disease could be found for any of the plasma NMR parameters, nor could T1 or lipid linewidth data distinguish between any patient group and healthy controls. However, the mean T2 was significantly shortened by about 15% for any kind of lung disease compared to healthy controls. Similar but less significant results were found for apolipoprotein-A levels. A linear discriminant function, calculated from the apolipoprotein-A and T2 data, did not improve the differentiation between malignant and nonmalignant lung disease but did improve the discrimination between tumor patients and healthy controls up to a sensitivity and specificity of 80 and 96.5%, respectively. T2 correlates inversely with plasma fibrinogen levels and the blood sedimentation rate and, therefore, appears to monitor a general inflammatory status of a tumor patient rather than the presence or absence of cancer. For all groups except healthy pregnant women, the lipid methylene composite signal linewidth correlates inversely with the fraction of mobile triglyceride present (mainly as VLDL), as estimated from resolution-enhanced spectra.

Electron spin resonance study in ternary metallic spin-glass Cu88-xMn12Tx alloys

Magnetisation and ESR studies on Cu88-xMn12Tx spin-glass alloys have been performed over the temperature range from 4.2 to 300 K where the concentration x of the nonmagnetic impurity T ( identical to Ni or Au) ranges from 0.5 to 2 at.%. The effects of the nonmagnetic impurities on the temperature dependences of the anisotropy energy, linewidth and resonance shift have been investigated. A large reduction in the degree of bottleneck and a rapid increase in the effective relaxation rate with increasing temperature for samples containing Au have been observed. The inverse susceptibility can be used to describe the ESR linewidth data.

Comparison of rotational relaxation rate laws to characterize the Raman Q-branch spectrum of CO at 295 K

We test the ability of the energy corrected sudden (ECS), modified exponential gap (MEG) and the statistical power-exponential gap (SPEG) rate laws to characterize line broadening and line interference in the CO Q-branch at 295 K. All three rate laws fit the experimental linewidth data. The ECS law is found to predict too much spectral collapse. The MEG and SPEG laws both adequately model spectral collapse, but with different implications about the role of dipolar and quadrupolar symmetry forces in CO:CO line broadening. From semiclassical calculations of CO linewidths, we conclude that the SPEG law with a restriction to even Δ J changes is the more physically correct model.

Polarization fluctuations as a source of electron spin resonance linewidths and relaxation of spin probes in KH2PO4-type of polar solids

While the CrO3−4 and SeO3−4 radicals have been used as spin probes in numerous electron spin resonance (ESR) studies of phase transitions in the KH2PO4-type of solids, discrepancies exist regarding the nature of molecular reorientations sensed by these probes, in particular, on whether the detected motion is thermally activated, with a well-defined activation energy, ΔE. Our new ESR data on these probes show that their linewidth, Γ, varies as Γ=Γ0+A exp(ΔE/kT)+B exp(−ΔE/kT). Here Γ0 is the temperature-independent, residual linewidth and A and B are parameters that depend on the ESR line splittings and the Zeeman field. ΔE has been estimated to be ≈0.22±0.02 eV (20±2 kJ/mol) for CrO3−4 in KD2AsO4, KD2PO4, NH4H2AsO4, ND4D2AsO4, and ND4D2PO4, and SeO3−4 in KD2PO4. The results suggest that the omission of the term B exp(−ΔE/kT) in all of the earlier analyses of the ESR linewidth data from these probes was the major cause of the reported non-Arrhenius behavior, especially in the high temperature (T≫Tc) regime. Measurements utilizing externally applied electric fields indicate that this new, Orbach-type, ESR line broadening process originates from thermally activated spin–flips via vibronic transitions, and ΔE provides a measure of the barrier height for the intrabond hydrogen transfer along the O–H⋅ ⋅ ⋅O bonds.

A hydrogen-1, chlorine-35, and lanthanum-139 NMR coordination study of the lanthanum (III) ion in aqueous solvent mixtures

A La(III) hydration study has been carried out for solutions of La(ClO4)3 and, in a preliminary way, La(NO3)3 in aqueous mixtures with acetone-d6 and Freon-12, using hydrogen-1, chlorine-35, and lanthanum-139 NMR spectroscopy. Low temperature, proton magnetic resonance experiments allowed the direct observation and area evaluation of separate signals for water molecules in the primary solvation shell of La(III) and in bulk medium. Measurements over a wide range of salt and solvent concentration gave a maximum La(III) hydration number of 6 and no evidence for inner-shell ion-pairing in La(ClO4)3 solutions. Chlorine-35 chemical shift and linewidth data in these solutions confirmed the absence of contact ionpairing. Hydration numbers of 3–4 for La(III) in several La(NO3)3 solutions clearly indicated inner-shell complex formation. Lanthanum-139 chemical shift and linewidth measurements for these systems revealed the presence of some process, possibly hydrolysis, in the La(ClO4)3 solutions at extremely high acetone-d6 concentrations.

Broadening and shifting of the Raman Q branch of HD

The line broadening and shifting of the vibrational Q branch in pure HD has been measured for transitions J=0 to 3 at room temperature over the density range 0.8 to 10.6 amagat. The shifting and broadening coefficients have been determined with an uncertainty of ±0.2×10−3 cm−1 /amagat, which now provides a discriminating test for various semiclassical and quantal theoretical calculations. The line broadening coefficients are compared with linewidth data from other spectroscopic branches and with measurements of the rates of state-to-state rotational energy transfer. Use of an exponential gap law for the rates of rotational energy transfer allows estimates to be made of the contributions to the linewidths from rotationally inelastic, elastic vibrational dephasing, and elastic reorientation processes. This analysis suggests that rotational energy transfer occurs approximately 30% faster in v=1 than in v=0.

Coherent anti-Stokes Raman spectroscopy of shock-compressed liquid nitrogen

Vibrational spectra of liquid nitrogen shock compressed to several high pressure/high temperature states were recorded using single-pulse multiplex coherent anti-Stokes Raman scattering. Vibrational frequencies, third-order susceptibility ratios, and linewidths are presented for the fundamental and several excited-state transitions. Vibrational frequencies were found to increase monotonically up to ≈17.5 GPa single shock and ≈30 GPa double shock. Above these pressures, the vibrational frequencies were observed to decrease with further increases in pressure. The decrease in vibrational frequency occurs in a pressure regime where the shocked nitrogen is becoming optically opaque. The consequence of the decrease in vibrational frequency on the Grüneisen mode gamma and its effect on the N2 equation of state is discussed. The transition intensity and linewidth data suggest that thermal equilibrium of the vibrational levels is attained in less than 10 ns at these high pressures and temperatures. Finally, the measured linewidths exhibit an almost linear dependence on shock temperature, and also suggest that the vibrational dephasing time has decreased to less than 1 ps at the highest pressures.