Single Broad Resonance Research Articles

B→D0∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ B\ o {D}_0^{\\ast } $$\\end{document} and Bs→Ds0∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}_s\ o {D}_{s0}^{\\ast } $$\\end{document} form factors from QCD light-cone sum rules

We present the first application of QCD light-cone sum rules (LCSRs) with B(s)-meson distribution amplitudes to the Bs→Ds0∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}_{(s)}\ o {D}_{(s)0}^{\\ast } $$\\end{document} form factors, where Ds0∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_{(s)0}^{\\ast } $$\\end{document} is a charmed scalar meson. We consider two scenarios for the D0∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_0^{\\ast } $$\\end{document} spectrum. In the first one, we follow the Particle Data Group and consider a single broad resonance D0∗2300\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_0^{\\ast }(2300) $$\\end{document}. In the second one, we assume the existence of two scalar resonances, D0∗2105\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_0^{\\ast }(2105) $$\\end{document} and D0∗2451\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_0^{\\ast }(2451) $$\\end{document}, as follows from a recent theoretically motivated analysis of B → Dππ decays. The B→D0∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ B\ o {D}_0^{\\ast } $$\\end{document} form factors are calculated in both scenarios, also taking into account the large total width of D0∗2300\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_0^{\\ast }(2300) $$\\end{document}. Furthermore, we calculate the Bs→Ds0∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}_s\ o {D}_{s0}^{\\ast } $$\\end{document} form factors, considering in this case only the one-resonance scenario with Ds0(2317). In this LCSRs calculation, the c-quark mass is kept finite and the s-quark mass is taken into account. We also include contributions of the two- and three-particle distribution amplitudes up to twist-four. Our predictions for semileptonic B→D0∗ℓνℓ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ B\ o {D}_0^{\\ast}\\ell {\ u}_{\\ell } $$\\end{document} and Bs→Ds0∗ℓνℓ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}_s\ o {D}_{s0}^{\\ast}\\ell {\ u}_{\\ell } $$\\end{document} branching ratios are compared with the available data and HQET-based predictions. As a byproduct, we also obtain the D0∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_0^{\\ast } $$\\end{document}- and Ds0∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {D}_{s0}^{\\ast } $$\\end{document}-meson decay constants and predict the lepton flavour universality ratios RD0∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ R\\left({D}_0^{\\ast}\\right) $$\\end{document} and RDs0∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ R\\left({D}_{s0}^{\\ast}\\right) $$\\end{document}.

Evidence of surface spin-glass behavior in NiFe2O4 nanoparticles determined using magnetic resonance technique

Abstract Nanosized nickel ferrite (NiFe2O4) is successfully synthesized by the sol-gel method using citric acid (C6H8O7) as fuel. The X-ray diffraction pattern of the as-synthesized sample shows formation of NiFe2O4 nanoparticles (NPs) as the main phase, with mean crystalline size ∼50 nm. While transmission electron microscopy (TEM) reveals nearly spherical morphology with mean particle diameter of 41 ± 5 nm, high-resolution TEM shows inter-planar distance (2.55 A) corresponding to the (1 1 3) plane of the spinel structure. Additionally, the Raman spectrum exhibits five Raman active modes (two A1g at 575 cm−1 and 710 cm−1; two Eg at 345 cm−1 and 670 cm−1; and one T2g at 497 cm−1) typical of NiFe2O4. X-band magnetic resonance (MR) data reveal a single broad resonance line in the whole temperature range (3.8 K ≤ T ≤ 300 K), with g-value decreasing monotonically from 3.10 ± 0.01 at 3.8 K to 2.77 ± 0.01 at 300 K. The temperature dependence of both resonance field and resonance linewidth show a remarkable change in the range of 60–70 K, herein credited to surface spin-glass behavior. The model picture used to explain the MR data assumes NPs with a core-shell structure. Below about 60–70 K the shell’s spin system progressively reveals a paramagnetic to spin-glass-like transition upon cooling, with a freezing temperature estimated at 2.1 ± 0.1 K. However, above about 60–70 K spins in the paramagnetic shell align along the NP’s core dipolar field, resulting in an effective enlarged nanoparticle size.

On the optical and magnetic studies of YCrO3 perovskites

In this paper we studied the Electron Paramagnetic Resonance (EPR) and Optical spectroscopies of mono disperse yttrium chromite (YCrO3) nanoparticles prepared by a modified polymeric precursor method. The particles crystallized in roughly spherical shape with size ranging from 100 to 200 nm. Diffuse reflectance spectrum exhibited very well defined bands related to the 4A2 → 4T2, 4A2 → 4T1, 4A2 → 2T1, 4A2 → 2E transitions, characteristic of Cr3+ (3d3, 2D5/2) ions in nearly octahedral symmetry. The crystalline field Dq, Racah parameters (B and C) and Dq/B, could be determined and the results indicated that Cr3+ ions are in a strong ligand field site. The EPR spectra of YCrO3 shows a single broad resonance in the whole range of temperature studied, 100–300 K. Combining optical and EPR results the effective g-values of the paramagnetic Cr3+ were estimated to be 1.97 and 1.98, respectively, typical of Cr3+ in orthorhombic crystal field environment. The onset of the antiferro-paramagnetic transition, TÑ140 K, attributed to Cr3+-Cr3+ exchange interaction (J = −41.5 cm−1) was determinate by means of Magnetization and EPR measurements. The results were discussed in terms of the magnetic short-rang spin-spin exchange interaction between pairs of Cr3+.

Syntheses of Group 4 ansa‐Trovacene Complexes and Conversion of [1]Silatrovacenophanes into Paramagnetic Metallopolymers by Ring‐Opening Polymerization

An improved protocol for the selective dilithiation of [V(η(5)-C(5)H(5))(η(7)-C(7)H(7))] has been developed, which afforded [V(η(5)-C(5)H(4)Li)(η(7)-C(7)H(6)Li)]·PMDTA (5; PMDTA=N,N,N',N'',N''-pentamethyldiethylenetriamine) in almost quantitative yield (98%). In the solid state, the species features a dimeric structure with two terminal and two bridging lithium atoms, with the latter connecting both sandwich subunits. Reaction with suitable Group 4 dihalide compounds enabled the isolation of highly strained silicon- and germanium-bridged [1]trovacenophanes 6 and 7. Similarly, reaction of 5 with Cl(2)Sn(2)tBu(4) afforded the rather unstrained complex [V(η(5)-C(5)H(4))(η(7)-C(7)H(6))Sn(2)tBu(4)] (8), which together with 7 represent the first trovacenophanes to incorporate heavier analogues of silicon in the ansa-bridge. Ring-opening polymerization reactions of [V(η(5)-C(5)H(4))(η(7)-C(7)H(6))SiRR'] (2a: R=R'=Me; 6: R=Me, R'=iPr) were performed by heating in a solution of toluene in the presence of the Karstedt catalyst, which resulted in the formation of the corresponding soluble poly(trovacenylsilanes) in yields of 41 and 33%, respectively. As estimated by gel permeation chromatography (GPC), the macromolecules possess molecular weights of M(n)=10,010 and 5580 g mol(-1) with polydispersity indices of 2.31 and 1.64 for 9 and 10, respectively. ESR spectroscopic studies on 9 and 10 revealed only a single broad resonance in each case without any identifiable (51)V hyperfine coupling.

Observation of coupling between surface plasmons in index-matched hole arrays

We measured the transmission of a large array of holes in an optically thick gold film, immersed in liquids of different refractive indices. For a large difference in refractive index between the substrate and the liquid $(\ensuremath{\Delta}n\ensuremath{\gtrsim}0.05)$, the transmission spectra contain separate resonances, due to surface plasmons propagating on each of the metal-to-dielectric interfaces. When the index difference is reduced we observe an avoided crossing between a strong low-energy mode and a weak high-energy mode. The low-energy mode becomes broader and gains amplitude at the expense of the high-energy mode. For an index-matched array, a single broad resonance remains. These observations provide direct evidence that the two surface plasmon modes on both sides of the interface are coupled.

Formula omitted] NMR study of [formula omitted

We have performed 11 B nuclear magnetic resonance (NMR) measurements on the single crystals of GdB 4 to investigate local electronic structure and 4f spin dynamics. 11 B NMR spectrum, Knight shift, spin–lattice and spin–spin relaxation rates, 1 / T 1 and 1 / T 2 , were measured down to 4 K at 8 T . 11 B NMR shift and linewidth are huge and strongly temperature-dependent due to the 4f moments. In addition, both are proportional to magnetic susceptibility, indicating that the hyperfine field at the boron site originates from the 4f spins of Gd. Below T N , the single broad resonance peak of 11 B NMR splits into several peaks reflecting the local magnetic fields due to antiferromagnetic spin arrangements. The spin–lattice relaxation rate, independent of temperature above T N , decreases significantly below T N confirming huge suppression of spin fluctuation.

11B NMR study of [formula omitted

We have performed 11B nuclear magnetic resonance (NMR) measurements on a single crystal of TbB 4 to investigate local electronic structure and 4f spin dynamics. 11B NMR spectrum, Knight shift, spin–lattice and spin–spin relaxation rates, 1 / T 1 and 1 / T 2 , were measured down to 5 K at 8 T. 11B NMR shift and linewidth are huge and strongly temperature-dependent due to the 4f moments. In addition, both are proportional to magnetic susceptibility, indicating that the hyperfine field at the boron site originates from the 4f spins of Tb. Below T N , the single broad resonance peak of 11B NMR splits into several peaks reflecting the local magnetic fields due to antiferromagnetic spin arrangements. The spin–lattice relaxation rate, independent of temperature above T N , decreases significantly below T N confirming huge suppression of spin dynamics.

Solid-State 23Na and 7Li NMR Investigations of Sodium- and Lithium-Reduced Mesoporous Titanium Oxides

Mesoporous titanium oxide synthesized using a dodecylamine template was treated with 0.2, 0.6, and 1.0 equiv of Li- or Na-naphthalene. The composite materials were characterized by nitrogen adsorption, powder X-ray diffraction, X-ray photoelectron spectroscopy, elemental analysis, thermogravimetric analysis, and solid-state 23Na and 7Li NMR spectroscopy. In all cases the wormhole mesoporosity was retained as evidenced by BET surface areas from 400 to 700 m(2)/g, Horvath-Kawazoe pore sizes in the 20 Angstroms range, and a lack of hysteresis in the nitrogen adsorption isotherms. Variable-temperature conductivity studies show that the Li-reduced materials are semiconductors, with conductivity values 3 orders of magnitude higher than those of the Na-reduced materials. Electrochemical measurements demonstrate reversible intercalation/deintercalation of Li+ ions into pristine mesoporous Ti oxides with good cycling capacity. Solid-state 23Na NMR reveals two distinct Na environments: one corresponding to sodium ions in the mesoporous channels and the other corresponding to sodium ions intercalated into the metal framework. 23Na NMR spectra also indicate that the relative population of the framework site increases with increased reduction levels. Solid-state 7Li NMR spectra display a single broad resonance, which increases in breadth with increased reduction levels, though individual resonances inferring the presence of channel and framework Li species are not resolved. Comparisons of the lithium chemical shifts with published values suggests an "anatase-like structure" with no long-range order in the least-reduced samples but a "lithium titanate-like structure" with no long-range order in the higher reduced materials.

Magnetic investigations of titanium‐doped gamma iron oxides dispersed in polymers

AbstractThe preparation and characterization of titanium‐doped iron oxides–styrene isoprene styrene block copolymer composites is reported. The precursor, as‐synthesized nanoparticles, contains akaganeite, maghemite, and titanium‐doped maghemite. Hysteresis loops obtained by SQUID measurements revealed an exchange biased field assigned to the presence of akaganeite nanoparticles. It was found that the coercive field and the exchange bias field decreases as the temperature of the sample is increased. The temperature dependence of the magnetization revealed a blocking temperature of about 220 K. The ESR spectra in the temperature range 150 K to about 300 K are single broad resonance lines. It was observed that the resonance line position is strongly temperature dependent due to the combined action of the external and molecular magnetic fields. The decrease of the resonance line width as the temperature is increased is governed by the reorientation of the magnetization. Thermally activated movements of magnetic nanoparticles within the soft phase (polyisoprene) of the matrix may also contribute to resonance line narrowing. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3432–3437, 2005

Single and double ionization of magnesium via four-photon excitation of the3p2S01autoionizing state: Experimental and theoretical analysis

Single and double ionization of ground state $\mathrm{Mg}$ atoms is observed in an atomic beam experiment in the $584--596\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ spectral range with a maximum intensity of $9\ifmmode\times\else\texttimes\fi{}{10}^{11}\phantom{\rule{0.3em}{0ex}}\mathrm{W}∕{\mathrm{cm}}^{2}$ and pulses of ns duration. The ${\mathrm{Mg}}^{+}$ spectrum consists of a single broad resonance whose position is very sensitive to laser intensity and it is attributed to the four-photon excitation of the doubly excited $3{p}^{2}\phantom{\rule{0.3em}{0ex}}^{1}S_{0}$ state. For intensities higher than $2\ifmmode\times\else\texttimes\fi{}{10}^{11}\phantom{\rule{0.3em}{0ex}}\mathrm{W}∕{\mathrm{cm}}^{2}$ a considerable double ionization yield is obtained. The ${\mathrm{Mg}}^{2+}$ spectra are composed of two lobes, each one dominating at different intensities. These observations can be interpreted by a sequential mechanism in which doubly charged ions are created by multiphoton resonant ionization of the excited $3{p}_{1∕2,3∕2}$ ${\mathrm{Mg}}^{+}$ states (with negligible contribution from the $3{s}_{1∕2}$ ionic ground state) after the single ion production has saturated. The population of these excited ionic states suggests the absorption of two photons above the first ionization threshold of $\mathrm{Mg}$. This interpretation is unambiguously confirmed by a complementary fluorescence experiment. Moreover, both ionization and fluorescence spectra as well as ionization yields are very well reproduced by a theoretical model based on a combination of density matrix and rate equations, taking into account the near-resonant coupling between the $3{p}^{2}\phantom{\rule{0.3em}{0ex}}^{1}S_{0}$ and $3p3d\phantom{\rule{0.3em}{0ex}}^{1}P_{1}$ autoionizing states and employing calculated parameters for both $\mathrm{Mg}$ and ${\mathrm{Mg}}^{+}$. It is thus pointed out that for visible ns pulses of moderate intensity the autoionizing resonances play a crucial role in the multiphoton sequential double ionization of alkaline-earth-metal atoms.

Resonances and thermonuclear reaction rates for charged particle collisions

We derive an approximate analytic expression for thermonuclear reaction rate for charged particles for the case that the cross section contains a single narrow or broad resonance described by a Breit-Wigner shape. An asymptotic series is obtained by making a Taylor series expansion which is exact at both the effective energy of the Gamow window and at the resonance energy. The resulting expression is uniformly valid as the effective energy and resonance energy coalesce or separate and as the resonance width is varied from narrow to broad. This is not true of conventional analytic approximations. We compare our uniform approximation with the exact reaction rate numerically and find it to be accurate over a large parameter range. We use our expressions to calculate the reaction rate for $^{12}\mathrm{C}(p,\ensuremath{\gamma})^{13}\mathrm{N}$.

Syntheses, structure and spectroscopic characterization of fac- and mer-Co(aepn)(CN) 3 and of their 13CN analogues [aepn= N-(2-aminoethyl)-1,3-propanediamine

Both facial ( 1) and meridional ( 3) isomers of Co(aepn)(CN) 3 [aepn= N-(2-aminoethyl)-1,3-propanediamine] and their 13CN analogues (facial 2 and meridional 4) have been prepared by two different synthetic approaches. 1 crystallizes in a monoclinic space group, P2 1/ c, and has one long and two short CN bonds. Meanwhile 3 crystallizes with a water of crystallization in the same space group ( P2 1/ n) and has one short and two long CN bonds. The 13C NMR spectrum of 4 shows three well-resolved resonances ( δ=143.53, 142.14, 132.85) for the three mer cyanide carbon atoms. In contrast, 3 has a single broad resonance in the range of δ=120–140, suggesting the presence of a dynamic process that is thought to be a trigonal twist of the three fac cyanide groups. According to the analyses of IR and Raman spectra, the Co(CN) 3 moiety of both isomers appears to have approximate C s molecular symmetry resulting in three IR- and Raman-active ν(CN) modes. Individual assignments of the vibrational peaks in the ν(CN) region have been confirmed by Raman band polarization measurements and 13CN isotope shifts. The stretching and bending modes of the metal-cyano groups in the low-frequency region (<600 cm −1) have also been analyzed.

Effect of Si doping on the electron spin resonance properties of ferrihydrite nanoparticles

Electron spin resonance investigations at 9.24 GHz in Si-doped two-line ferrihydrite (Si/FeOOH/spl middot/nH/sub 2/O) nanoparticles of size /spl sime/4 nm are reported for x=Si/(Si+Fe)=0, 0.02, 0.05, 0.10 and 0.15. For all samples, a single broad resonance near g/spl sime/2 is observed; however with increase in x, both the resonance field H/sub r/ and linewidth /spl Delta/H increase but integrated intensity I of the line decreases, similar to the observed decrease in magnetization with x. These observations suggest that the observed resonance is due to uncompensated Fe/sup 3+/ surface spins. Temperature variation (300 K to 80 K) of H/sub r/ and /spl Delta/H for x=0.05 shows a downward shift (/spl delta/H/sub r/) of the line with a rapid increase in /spl Delta/H so that /spl delta/H/sub r//spl prop/(/spl Delta/H)/sup 3/ predicted for randomly oriented nanoparticles is observed.

Microsphere resonators strongly coupled to a plane dielectric substrate: coupling via the optical near field.

A model is proposed that describes the essential optical process in the recently observed resonant light scattering from a microsphere resonator that is strongly coupled to the substrate. The experimentally observed field patterns across the resonance can be reproduced quite well by a numerical calculation taking into account only a few vector spherical waves that are converted from nonpropagating to propagating waves at the substrate surface. Explicit consideration of the multiple-reflection effect is not necessary to reproduce the experimental results. Comparison of the experiment and the calculation suggests the splitting of degenerate resonance modes that have different azimuthal mode numbers within a single broad resonance line. These results are discussed on the basis of the strongly coupled nature of the system.

ESR Study of the plasma polymerizations of trimethylsilane and methane

Electron Spin Resonance (ESR) was used to study, at the molecular level, the plasma polymerization of trimethylsilane (TMS) and methane. Direct ESR analysis of the plasma coated Al substrate required the use of a novel ESR technique. TMS plasma deposit on Al showed a single broad resonance line near g = 2.003. The signal was stable in vacuum and decayed on exposure to air, with a significant fraction persisting for days. Results show that this signal arises from silicon dangling bonds. Identical TMS signals were observed from films prepared by the DC cathodic or the AF glow discharge method but their decay rates were different. In contrast, the deposition of methane produced two distinct types of carbon-based signals depending upon the method of deposition. TMS or CH4 films deposited by the DC cathodic method showed slow signals decay and high refractive indices value. While the use of Al as the substrate showed plasma-coating radicals, only substrate radicals were observed when PE was used as the substrate. The nature of radicals formed depends not only on the deposition method used but also on the substrate type.

Solid-State Nuclear Magnetic Resonance Study of the Microporous Aluminophosphate AlPO4-41

Highly crystalline aluminophosphate molecular sieve AlPO4-41 has been synthesized using dipropylamine as the templating molecule. Materials in the as-made, calcined never rehydrated, and calcined rehydrated forms have been characterized by solid-state NMR spectroscopy using 27Al and 31P magic angle spinning (MAS), two-dimensional 27Al 5Q-MAS, and 27Al → 31P CP/MAS techniques. Both 31P MAS and 27Al 5Q-MAS spectra of the as-synthesized AlPO4-41 exhibit several resonances, all of them being assigned to framework atoms. Spectra are drastically modified after calcination. While the 31P MAS spectrum of the calcined never rehydrated solid is composed of a single broad resonance at ca. −30.5 ppm, five signals can be observed after rehydration. Rehydration slightly modifies the unit cell parameters, particularly the b axis and γ angle, but it is a completely reversible process. 27Al NMR spectroscopy shows that water preferentially coordinates one of the five nonequivalent aluminum sites of the structure and transforms it into a six-coordinated species. The position of this site in the structure has been unambiguously determined from P−O−Al framework connectivities and confirmed by 1H → 31P CP/MAS experiments. The location of the amine in the pores of the as-synthesized AlPO4-41 was also estimated, suggesting that a specific interaction with one framework oxygen could account for the special shape of the channels (monoclinic space group P1121).

Identification of the glueballs and the scalar meson nonet of lowest mass

We discuss the theoretical expectations and phenomenological evidence for the lightest glueballs and the members of the meson nonet with quantum numbers \(J^{PC}=0^{++}\). We reconsider the recent evidence for candidate states with masses below \(\sim\)1700 MeV, but include also the results from earlier phase-shift analyses. Arguments are presented to classify the scalars \(f_0(980)\) and \(f_0(1500)\) as members of the \(0^{++}\) nonet, with a mixing rather similar to that of the pseudoscalars \(\eta'\) and \(\eta\). The S-wave states called \(f_0(400-1200)\) and \(f_0(1370)\) are considered as different signals from a single broad resonance, which we take to be the lowest-lying \(0^{++}\) glueball. This state together with \(\eta(1440)\) and \(f_J(1710)\) with spin \(J=2\) form the basic triplet of binary gluonic bound states. We argue that these hypotheses are consistent with what can be expected theoretically.

Identification of the glueballs and the scalar meson nonet of lowest mass

We discuss the theoretical expectations and phenomenological evidence for the lightest glueballs and the members of the meson nonet with quantum numbers J^PC=0^{++}. We reconsider the recent evidence for candidate states with masses below ~1700 MeV, but include also the results from earlier phase-shift analyses. Arguments are presented to classify the scalars f_0(980) and f_0(1500) as members of the 0^{++} nonet, with a mixing rather similar to that of the pseudoscalars eta' and eta. The S-wave states called f_0(400-1200) and f_0(1370) are considered as different signals from a single broad resonance, which we take to be the lowest-lying 0^{++} glueball. This state together with eta(1440) and f_J(1710) with spin J=2 form the basic triplet of binary gluonic bound states. We argue that these hypotheses are consistent with what can be expected theoretically.

Single-photon and multiphoton processes causing resonance in the transmission of electrons by a single potential barrier in a radiation field

Simulations of electrons tunneling in a barrier for which the height varies sinusoidally with time show resonances increasing the transmitted current. For square barriers, these resonances occur when electrons are promoted above the barrier by absorbing quanta from the barrier oscillations, and the barrier length is an integer multiple of one-half of the de Broglie wavelength. For several barriers having other profiles, we find that there is a single broad resonance centered at a wavelength equal to 0.9 times the wavelength for a photon having the energy to take the particle exactly to the top of the barrier. We attribute this difference to the fact that quanta may only be exchanged at the ends of a square barrier, whereas quanta are exchanged throughout the full length of barriers having other profiles—especially in regions of high electric field intensity. A Floquet expansion is used to examine the change in transmission caused by barrier modulation for electrons at the different energies caused by the exchange of quanta. We find that the wavelengths for resonance are proportional to the number of quanta absorbed by the particles, and attribute this observation to the requirement that specific values of absorbed energy are necessary for resonance. The increase in transmission caused by absorbing M quanta is proportional to the Mth power of the power flux density of the radiation causing barrier modulation. Thus, as the power is increased, the total transmission (including all energies) shows greater structure due to multiphoton processes. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 75: 417–427, 1999

Deuteron resonance studies in CeNiInD x system

Deuteron NMR studies have been performed in CeNiInD x system ( x = 0.33 and 1.01) in the temperature range 150–300 K. For x = 0.33, a single broad asymmetric resonance line appears at all temperatures. This means that the rapid diffusion of deuteron atoms averages out the quadrupolar splitting and hence a single line results. On the other hand for x = 1.01, observation of quadrupolar splitted resonance lines indicates that deuterons occupy two non-equivalent interstitial sites. The quadrupolar interaction parameters are obtained by fitting the experimental spectra with η = 0 and are compared with those obtained from a point charge calculation. Most probable sites for deuterons in CeNiInD 1.01 system are then proposed.