Laser-induced-fluorescence Fourier transform spectrometry of the XOg+ state of I2: Extensive analysis of the BOu+ → XOg+ fluorescence spectrum of 127I129I and 129I2

An extensive rotational analysis of the vibrational levels of the XO_g⁺ state of ¹²⁷I¹²⁹I (5 ≤ v″ ≤ 110) and ¹²⁹I₂ (4 ≤ v″ ≤ 108) has been done from laser-induced-fluorescence analyzed with a Fourier transform spectrometer. The usual Dunham relationships are checked. For the range explored the lines can be recalculated with an accuracy better than 0.010 cm⁻¹ and even 0.005 cm⁻¹ for low J values. Checks are done from absolute hyperfine measurements.     

Observation of the decaya 2 − (1320)→π − η′

The reaction ^– C ^– C has been studied at 36 GeV/c. A clear signal for the decaya ₂ ^– (1320) ^– · is observed in the ^– mass spectrum. The measured ratio of branchings is BR (a ₂ ^{– –} )/BR(a ₂ ^{– –} );(3.4±0.8±0.5)·10^–2.     

Reanalysis of the photoassociation spectrum of 133Cs2 （6P3/2） lg state

Reanalysis of the photoassociation spectrum of the weakly binding （6S1/2 ＋ 6P3/2） lg 133Cs2 levels, reported in the previous study [J. Mol. Spectro. 255 （2009） 106], is performed by using a Lu-Fano graph coupled to the improved LeRoy- Bernstein formula including two additional modified terms. A more accurate coefficient （c3） is obtained for the leading long-range potential （-c3/R3） of a diatomic molecule.     

Extended analysis of the Ar VII spectrum in the vacuum ultraviolet region

The current status of the determination of corrections to the hyperfine splitting of the ground state in hydrogen is considered. Improved calculations are provided taking into account the most recent value for the proton charge radius. Comparing experimental data with predictions for the hyperfine splitting, the Zemach radius of the proton is deduced to be 1.045(16) fm. Employing exponential parametrizations for the electromagnetic form factors we determine the magnetic radius of the proton to be 0.778(29) fm. Both values are compared with the corresponding ones derived from the data obtained in electron-proton scattering experiments and the data extracted from a rescaled difference between the hyperfine splittings in hydrogen and muonium.     

Theoretical analysis of the IR spectrum of methyl-3,4-anhydro-α-D-talohexopyranoside

A detailed interpretation of the IR spectrum of methyl-3,4-anhydro-α-D-talohexopyranoside that is based on complete calculation of normal vibration frequencies and absolute IR absorption band intensities of the molecule and a comparison of the results obtained with the corresponding experimental data is given for the first time. The influence of the epoxy group on the absorption bands characteristic of the pyranose ring has been analyzed. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 5, pp. 597–605, September–October, 2008.     

Unusual behaviour of conductivity and superconductivity in solid Sn−Xe mixtures

We have measured the normal statedc conductivity , the superconducting transition temperatureT _c and the critical superconducting currentI _c0 of frozen Sn–Xe mixtures in dependence of the Sn atomic fractionc. A new, high-T _c phase is observed forc between 0.58±0.02 and 0.74±0.02. This phase has aT _c-value of about 5.7 K, it shows a strong decrease in and inI _c0 and transforms into disordered Sn during annealing between 15 K and 50 K.It is a pleasure for us to dedicate this paper to Prof. Dr. S. Methfessel on the occasion of his 60^th birthday.This work was supported by the Deutsche Forschungs-gemeinschaft     

The pentad of 12CD4: Line parameter analysis of the IR spectrum in the range 1775–2350 cm−1

In a previous paper (J.-E. Lolck, G. Poussigue, E. Pascaud, and G. Guelachvili, J. Mol. Spectrosc. 111, 235–274 (1985)), we presented the first comprehensive assignment and wavenumber analysis of high-resolution (nearly Doppler limited) rotation-vibrational spectra of the interacting upper states of the ν₁, ν₃, 2ν₂, ν₂ + ν₄, and 2ν₄ bands of the ¹²CD₄ pentad. The present paper continues this work by describing the determination and quality estimation of experimental infrared line strengths from the Fourier transform spectra. These line strengths are interpreted in terms of a theoretical model which contains, as parameters, the dipole moment derivatives and the main Hermann-Wallis coefficients of the infrared-allowed bands: ν₃(F₂), ν₂ + ν₄(F₂), and 2ν₄(F₂). This model also explains the appearance of infrared transitions to upper states, forbidden in infrared in an isolated state approach, through the mixing of states caused by the intervibrational interactions. The intensity analysis leads to the determination of all six parameters in the model and to a reproduction of the experimental intensities with a precision comparable to the experimental accuracy of 10 to 15%.     

Theoretical analysis of the ship noise demodulation spectrum harmonic clan feature

The structure law of the ship noise demodulation spectrum harmonic clan feature and corresponding applications to the recognition problem are studied by theoretical derivation and sample analysis.In order to recognize the propeller blade-number,the ship propeller cavitation noise model is established on the basis of five hypotheses.Further,the mathematical expressions of the structure law are deduced by the model.And the class space of the propeller blade-number is analysed mathematically.The results can be applied to target recognition as expert knowledge.Finally,the demodulation spectrum harmonic clans of experiment samples are obtained by using the wavelet packet.The structure law is validated by the statistic analysis of experiment samples.It is shown that the statistical average results of experiment samples are consistent very well with the theory structure law,and 78.6% of the samples basically accord with the theory structure law.     

Analysis of the CRDS spectrum of 18O3 between 6950 and 7125 cm−1

The absorption spectrum of the ¹⁸O₃ isotopologue of ozone was recorded by CW-Cavity Ring Down Spectroscopy in the 6950–7125 cm^?1 region. The typical noise equivalent absorption of the recordings is α_min ≈1×10^?10 cm^?1. The spectrum is dominated by three very weak bands: 3ν₁+5ν₃ near 7009 cm^?1 and the ν₂+7ν₃ and 4ν₂+5ν₃ interacting bands near 7100 cm^?1. In total 260, 206 and 133 transitions were assigned for the 3ν₁+5ν₃, ν₂+7ν₃ and 4ν₂+5ν₃ bands, respectively. The line positions of the 3ν₁+5ν₃ band were modelled using an effective Hamiltonian (EH) model involving two dark states – (6 0 1) and (2 5 2) – in interaction with the (3 0 5) bright state. The EH model developed for the ν₂+7ν₃ and 4ν₂+5ν₃ bands involves only the (0 1 7) and (0 4 5) interacting bright states. Line positions could be reproduced with rms deviations on the order of 0.01 cm^?1 and the dipole transition moment parameters were determined for the three observed bands. The obtained set of parameters and the experimentally determined energy levels were used to generate a list of 984 transitions of the three bands which is provided as Supplementary Material.     

Quantitative analysis of the self-absorption and reemission effects on the emission spectrum of photoluminescence in right-angle excitation–detection configuration

A theoretical approach based on differential radiative transport is proposed to quantitatively analyze the selfabsorption and reemission effects on the emission spectrum for right angle excitation–detection photoluminescence measurements,and the wavelength dependence of the reemission effect is taken into account.Simulations and experiments are performed using rhodamine 6G solutions in ethanol as model samples.It is shown that the self-absorption effect is the dominant effect on the detected spectrum by inducing pseudo red-shift and reducing total intensity;whereas the reemission effect partly compensates for signal decrease and also results in an apparent signal gain at the wavelengths without absorption.Both effects decrease with the decrease in the sample concentration and the propagation distance of the emission light inside the sample.We therefore suggest that diluted solutions are required for accurate photoluminescence spectrum measurements and photoluminescence-based measurements.     

Light-front quark model and analysis of the spectrum of photons from inclusive B → X s γ decays

The electroweak-decay width Γ(B → X _s γ) is investigated in a light-front (LF) constituent quark model. A new partonlike formula is derived that establishes a simple relation between Γ(B → X _s γ) and the b → sγ decay width. A treatment of the b quark as an on-mass-shell particle and the inclusion of effects that arise from the transverse motion of the b quark in the B meson are basic features of this approach. Adopting different b-quark LF distribution functions, both phenomenological ones and those that are derived from constituent quark models, and neglecting perturbative corrections, we compute the photon energy spectra and the moments of the shape function. It is shown that the LF approach can be matched completely with a heavy-quark expansion (HQE), provided that the constituent b-quark mass is redefined in a way similar to that used in HQE to define the pole mass of the b quark. In this way, the correction to first order in 1/m _b can be eliminated from the total width in agreement with the general statement of HQE. We also show that the photon energy spectra calculated in the LF approach agree well with those obtained in the model of Altarelli et al., provided that the same distribution function is used as an input in both cases. Despite the simplicity of the model, our results are in fairly good agreement both with HQE predictions and with available experimental data.     

The near infrared (0.8−2.6µm) absorption spectrum of a dense sodium vapor and possible mechanisms of the spectrum formation

The absorption coefficient of a dense sodium vapor (N₀ ～ 10¹⁷–10¹⁸ cm^{? 3}) in the near infrared spectral range (0.8–2.6 µm) was measured in a homogeneously heated isolated cell. In the range of parameters studied, the sample exhibits significant absorption. Neither the observed spectral features nor the measured absorption coefficients can be explained using the existing notions of the possible absorption mechanisms (absorption due to a forbidden intercombination transition, collision-induced processes, the trimer vapor component, and many-particle effects) and the available data.     

Millimetre-wave and Fourier transform infrared spectra between 325 cm−1 and 4720 cm−1 of BrCN and global rovibrational analysis of the main isotopomers

The infrared absorption spectrum of BrCN has been recorded in the re?ion 325–4720 cm^?1 with a Bruker 120 HR interferometer. More than 30 000 lines have been measured and most of them have been assigned: 10734 lines for 151 bands and 10993 lines for 150 bands of ⁷⁹Br¹²C¹⁴N and ⁸¹Br¹²C¹⁴N, respectively. Also new millimetre-wave spectra were measured for the vibrational excited states lying between 1000 cm^?1 and 1400 cm-′. After a band by band analysis of these transitions, rovibrational global analyses have been performed for both isotopomers using all available experimental data. The rotational I-type resonance and the anharmonic resonance associated with k_l22 are taken into account in one-step diagonalization procedures. Sets of 73 molecular parameters are obtained for both isotopomers. It is shown that the existing equilibrium structure is likely to be reliable. The vibrational dependence of the quartic centrifugal distortion constant is analysed for the linear triatomic molecules studied so far.     

Observation ofμ − spin precession in ferromagnetic Ni and giant hyperfine anomaly

A ^–SR signal in nickel was found representing the first observation of ^–SR in ferromagnetic materials, and the hyperfine anomaly was determined to be –2.82±0.08% in comparison with the hyperfine field at dilute Co in Ni known from NMR.