Absorption in Ultra-Peripheral Nucleus-Atom Collisions in Crystal

The Glauber theory description of particle- and nucleus-crystal Coulomb interactions at high-energy is developed. The allowance for the lattice thermal vibrations is shown to produce strong absorption effect which is of prime importance for quantitative understanding of the coherent Coulomb excitation of ultra-relativistic particles and nuclei passing through the crystal.Comment: 8 pages, LaTe

High resolution infrared and Raman spectra of 13C12CD2: The CD stretching fundamentals and associated combination and hot bands

11 pags.; 4 figs.; 9 tabs.© 2015 AIP Publishing LLC. Infrared and Raman spectra of mono 13C fully deuterated acetylene, 13C12CD2, have been recorded and analysed to obtain detailed information on the C—D stretching fundamentals and associated combination, overtone, and hot bands. Infrared spectra were recorded at an instrumental resolution ranging between 0.006 and 0.01 cm−1 in the region 1800–7800 cm−1. Sixty new bands involving the ν 1 and ν 3 C—D stretching modes also associated with the ν 4 and ν 5 bending vibrations have been observed and analysed. In total, 5881 transitions have been assigned in the investigated spectral region. In addition, the Q branch of the ν 1 fundamental was recorded using inverse Raman spectroscopy, with an instrumental resolution of about 0.003 cm−1. The transitions relative to each stretching mode, i.e., the fundamental band, its first overtone, and associated hot and combination bands involving bending states with υ 4 + υ 5 up to 2 were fitted simultaneously. The usual Hamiltonian appropriate to a linear molecule, including vibration and rotation l-type and the Darling–Dennison interaction between υ 4 = 2 and υ 5 = 2 levels associated with the stretching states, was adopted for the analysis. The standard deviation for each global fit is ≤0.0004 cm−1, of the same order of magnitude of the measurement precision. Slightly improved parameters for the bending and the ν 2 manifold have been also determined. Precise values of spectroscopic parameters deperturbed from the resonance interactions have been obtained. They provide quantitative information on the anharmonic character of the potential energy surface, which can be useful, in addition to those reported in the literature, for the determination of a general anharmonic force field for the molecule. Finally, the obtained values of the Darling–Dennison constants can be valuable for understanding energy flows between independent vibrations.The Bologna authors acknowledge the Università di Bologna and the financial support of the Ministero dell’ Istruzione dell’Università e della Ricerca (PRIN 2012 “Spettroscopia e Tecniche computazionali per la ricerca Astrofisica, atmosferica e Radioastronomica”). D.B. and R.Z.M. acknowledge the financial support of the Ministry of Economy and Competitiveness through Research Grant No. FIS2012-38175.Peer Reviewe

Flow Index: a novel, non-invasive, continuous, quantitative method to evaluate patient inspiratory effort during pressure support ventilation

Background: The evaluation of patient effort is pivotal during pressure support ventilation, but a non-invasive, continuous, quantitative method to assess patient inspiratory effort is still lacking. We hypothesized that the concavity of the inspiratory flow-time waveform could be useful to estimate patient’s inspiratory effort. The purpose of this study was to assess whether the shape of the inspiratory flow, as quantified by a numeric indicator, could be associated with inspiratory effort during pressure support ventilation. Methods: Twenty-four patients in pressure support ventilation were enrolled. A mathematical relationship describing the decay pattern of the inspiratory flow profile was developed. The parameter hypothesized to estimate effort was named Flow Index. Esophageal pressure, airway pressure, airflow, and volume waveforms were recorded at three support levels (maximum, minimum and baseline). The association between Flow Index and reference measures of patient effort (pressure time product and pressure generated by respiratory muscles) was evaluated using linear mixed effects models adjusted for tidal volume, respiratory rate and respiratory rate/tidal volume. Results: Flow Index was different at the three pressure support levels and all group comparisons were statistically significant. In all tested models, Flow Index was independently associated with patient effort (p < 0.001). Flow Index prediction of inspiratory effort agreed with esophageal pressure-based methods. Conclusions: Flow Index is associated with patient inspiratory effort during pressure support ventilation, and may provide potentially useful information for setting inspiratory support and monitoring patient-ventilator interactions

Carbon suboxide: the vibrational dependence of the v7 bending potential function

Data on the vibrational energy levels and rotational constants of carbon suboxide for the low-wavenumber bending mode ν7 are reviewed, in the ground-state manifold, and in the ν2-, ν3-, ν4-, and ν2 + ν4-state manifolds. Following the procedure developed by Duckett, Mills, and Robiette [J. Mol. Spectrosc. 63, 249 (1976)] the data have been inverted to give the effective bending potential in ν7 for each of these five states. Values are obtained for various other parameters in the effective vibration-rotation Hamiltonian. The potential and rotational constants in ν2 + ν4 are given to a close approximation by linear extrapolation from the ground state through the ν2 and ν4 states

Communication: Observation of homonuclear propensity in collisional relaxation of the 13C12CD2 (v2 = 1) isotopologue of acetylene by stimulated Raman spectroscopy

4 p.: gráf.We report the first experimental observation of homonuclear propensity in collisional relaxation of a polyatomic molecule. A pump-probe stimulated Raman setup is used to pump population to a single rotational level of the v2 = 1 vibrationally excited state in 13C12CD2 and then monitor the redistribution of the rotational population that has taken place after a fixed delay. The Q-branch of the 2ν2–ν2 band shows a pattern of intensity alternation between the even and the odd rotational components, with the greater intensities always corresponding to the rotational levels with the same parity as the one where all the population was initially deposited. The effect can be explained by the existence of a propensity rule that favors collisional relaxation between rovibrational levels of the same parity. © 2011 American Institute of Physics.Funding received from the Spanish Ministry of Science and Innovation through research Grant No. FIS2009-08069; support from CONSOLIDER-INGENIO 2010 Program CSD2009-00038Peer reviewe

Empirical anharmonic force field and equilibrium structure of hypochlorous acid, HOCl

The cubic and quartic force fields of HOCl are investigated on the basis of the most recent experimental data on vibration-rotation interaction constants and anharmonicity constants. Some discrepancies with respect to previously reported ab initio results are found and discussed. The geometrical parameters of this molecule are also evaluated from recent data on the equilibrium values of the moments of inertia.© 1996 Published by Elsevier B.V.Cooperation Program between CNR of Italy and CSIC of Spain. Spanish DGICYT, project PB93-0138.Peer Reviewe

The nu1+nu5 high resolution infrared band of FClO3

The high resolution infrared spectra of the mono isotopic species (FClO3)-Cl-35-O-16, (FClO3)-Cl-37-O-16, (FClO3)-Cl-35-O-18 and (FClO3)-Cl-37-O-18 have been analysed in the region of the nu(1) + nu(5) perpendicular combination band, from 1540 to 1680 cm(-1). For all the isotopologues the nu(1) + nu(5) band is of medium intensity at the recording conditions. In total, about 2400, 2000, 2600 and 2700 transitions have been assigned for (FClO3)-Cl-35-O-16, (FClO3)-Cl-37-O-16, (FClO3)-Cl-35-O-18 and (FClO3)-Cl-37-O-18, respectively. The data for each band have been analysed on the basis of the usual Hamiltonian for a degenerate state of a molecule of C-3v symmetry. In addition, two interaction terms have been considered active within the v(1) = v(5) = 1 state, with Delta l = 0, Delta k = +/- 3 and Delta l = Delta k = +/- 2 selection rules. The ro-vibration parameters of the v(1) = v(5) = 1 states have been obtained, together with the band origins. Combining the nu(1) + nu(5) origins with those of the nu(1) and nu(5) fundamentals, the anharmonicity constant x(15) has been derived for the four molecules and compared to the corresponding value calculated ab initio

The nu4 and nu2+nu5 high resolution infrared bands of F35Cl18O3 and F37Cl18O3

none3noneE. Cané; L. Fusina; K. BurczykE. Cané; L. Fusina; K. Burczy