Theoretical Study of Pressure Broadening of Lithium Resonance Lines by Helium Atoms

Quantum mechanical calculations are performed of the emission and absorption profiles of the lithium 2s-2p resonance line under the influence of a helium perturbing gas. We use carefully constructed potential energy surfaces and transition dipole moments to compute the emission and absorption coefficients at temperatures from 200 to 3000 K at wavelengths between 500 nm and 1000 nm. Contributions from quasi-bound states are included. The resulting red and blue wing profiles are compared with previous theoretical calculations and with an experiment, carried out at a temperature of 670 K.Comment: 10 figure

Theoretical Study of Sodium and Potassium Resonance Lines Pressure Broadened by Helium Atoms

We perform fully quantum mechanical calculations in the binary approximation of the emission and absorption profiles of the sodium $3s$-$3p$ and potassium $4s$-$4p$ resonance lines under the influence of a helium perturbing gas. We use carefully constructed potential energy surfaces and transition dipole moments to compute the emission and absorption coefficients at temperatures from 158 to 3000 K. Contributions from quasi-bound states are included. The resulting red and blue wing profiles agree well with previous theoretical calculations and with experimental measurements.Comment: 16 figure

The Solar Wind Charge-eXchange contribution to the Local Soft X-ray Background. Model to data comparison in the 0.1-1.0 keV band

The major sources of the Soft X-ray Background (SXRB), besides distinct structures as supernovae and superbubbles (e.g. Loop I), are: (i) an absorbed extragalactic emission following a power law, (ii) an absorbed thermal component ~2x10^6 K) from the galactic disk and halo, (iii) an unabsorbed thermal component, supposedly at 10^6 K, attributed to the Local Bubble and (iv) the very recently identified unabsorbed Solar Wind Charge-eXchange (SWCX) emission from the heliosphere and the geocorona. We study the SWCX heliospheric component and its contribution to observed data. In a first part, we apply a SWCX heliospheric simulation to model the oxygen lines (3/4 keV) local intensities during shadowing observations of the MBM12 molecular cloud and a dense filament in the south galactic hemisphere with Chandra, XMM-Newton, and Suzaku telescopes. In a second part, we present a preliminary comparison of SWCX model results with ROSAT and Wisconsin surveys data in the 1/4 keV band. We conclude that, in the 3/4 keV band, the total local intensity is entirely heliospheric, while in the 1/4 keV band, the heliospheric component seems to contribute significantly to the local SXRB intensity and has potentially a strong influence on the interpretation of the ROSAT and Wisconsin surveys data in terms of Local Bubble hot gas temperature.Comment: 15 pages, 7 figures, 2 tables, 'From the Outer Heliosphere to the Local Bubble' ISSI workshop, Bern October 200

Environmental DNA Based Surveillance for the Highly Invasive Carpet Sea Squirt Didemnum vexillum : A Targeted Single-Species Approach

Funding Information: The authors would like to thank the site operators, owners and Solway Firth Partnership for allowing access and sample collection at studied sites visited during this study. Thanks also to Frank Armstrong, Katy Beaton, Maria Campbell, Pablo Dias, James Dooley, Judith Horrill, Nial McLeod, Warren Murray, Andrea Taylor, Joe Triscott, and Bill Turrell for contributing to field work and sample collection. The authors thank National Museums Scotland and particularly Fiona Ware for the loan of reference material (specimen register number NMS.Z.2015.82.8, 9 and 14 and NMS.Z.2018.2.2) which was used in the present study. KS thank the Japan Society for the Promotion of Science for post-doctoral fellowship funding.Peer reviewedPublisher PD

Dynamics of OH(2Pi)-He collisions in combined electric and magnetic fields

We use accurate quantum mechanical calculations to analyze the effects of parallel electric and magnetic fields on collision dynamics of OH(2Pi) molecules. It is demonstrated that spin relaxation in 3He-OH collisions at temperatures below 0.01 K can be effectively suppressed by moderate electric fields of order 10 kV/cm. We show that electric fields can be used to manipulate Feshbach resonances in collisions of cold molecules. Our results can be verified in experiments with OH molecules in Stark decelerated molecular beams and electromagnetic traps.Comment: 20 pages, 5 figures, submitted to Faraday Discuss. 142: Cold and Ultracold Molecule

Recombination of H-2 by Raman association in the early universe

Contains fulltext : 35447.pdf (publisher's version ) (Open Access)We investigate the contribution that Raman association makes to H-2 production in the early universe at redshifts 10 <= z <= 10(4). The Raman process involves inelastic scattering of electromagnetic radiation off two colliding hydrogen atoms, taking away kinetic and binding energy and leaving bound H-2. We calculate the inelastic cross sections and rate coefficients for this process and determine the Raman association rate in the cosmic background radiation field present during the early stages of the universe. A comparison with other H-2-forming reactions is made

The Solar Wind Charge-eXchange Contribution to the Local Soft X-ray Background

International audienceThe major sources of the Soft X-ray Background (SXRB), besides distinct structures as supernovae and superbubbles (e.g. Loop I), are: (i) an absorbed extragalactic emission following a power law, (ii) an absorbed thermal component (∼2×106 K) from the galactic disk and halo, (iii) an unabsorbed thermal component, supposedly at 106 K, attributed to the Local Bubble and (iv) the very recently identified unabsorbed Solar Wind Charge-eXchange (SWCX) emission from the heliosphere and the geocorona

RECOMBINATION OF H 2 BY RAMAN ASSOCIATION IN THE EARLY UNIVERSE

ABSTRACT We investigate the contribution that Raman association makes to H 2 production in the early universe at redshifts 10 ≤ z ≤ 10 4 . The Raman process involves inelastic scattering of electromagnetic radiation off two colliding hydrogen atoms, taking away kinetic and binding energy and leaving bound H 2 . We calculate the inelastic cross sections and rate coefficients for this process and determine the Raman association rate in the cosmic background radiation field present during the early stages of the universe. A comparison with other H 2 -forming reactions is made