Reactions of N+ (3P) ions with H2 and HD molecules at low temperatures

International audienceContext. This work is motivated by the necessity to take account of both the nuclear spin symmetries of H 2 and the spin-orbit interaction of N + ions in order to investigate gas phase reactions in interstellar chemistry, leading to the formation of nitrogenous and deuterated compounds. Aims. The main objective in this work is to determine the rate coefficients for each possible initial quantum state of the reactants N + (3 P j) + H 2 (J) (and their isotopic variants). Only in this way does it become possible both to analyse experimental data and to develop realistic applications to interstellar chemical models to constrain the gas phase chemistry of ammonia and its isotopologues. Methods. A statistical treatment is presented of state selective reactive collisions involving N + ions in fine structure state j with H 2 or HD molecules in a rotation level J of the ground vibration state, leading either to the production of NH + ions and H in the case of the H 2 reactant, and to the production of either NH + ions or ND + in the case of the HD reactant. The energies of fine structure states (j = 0, 1, 2) of the N + ions are treated on an equal footing with the other energies of internal motions. All fine structure states are considered to be reactive. Results. Cross sections for state-to-state collisions are calculated for collision energies ranging from 0.1–30 meV. These cross sections are then averaged over the kinetic energies of the reactants for each (J, j) to obtain the rate coefficients for a range of kinetic temperatures 10–200 K. The exo/endothermicity of the reactions involving N + (3 P j) + H 2 (J) (and isotopic variants) is derived from the difference ∆E e between the dissociation energies of the electronic molecular potentials of NH + and H 2. The value ∆E e = 101 meV is found to satisfactorily reproduce the experiments performed with ortho-H 2 and to a lesser extent with para-H 2. This value is used to determine the rate coefficient of the N + + HD reaction leading to the formation of ND +. The calculated value is consistent with the available experimental data. Conclusions. The present results allow for the determination of reaction rate coefficients for any given distribution of specific fine structure and rotational state populations of the reactants. In interstellar conditions, where N + is in its 3 P 0 state and para-and ortho-H 2 respectively in J = 0 and J = 1. Our results enable a study of the influence of the ortho/para evolution of molecular hydrogen on the formation of nitrogen compounds

Saccharopolyspora cebuensis sp. nov., a novel actinomycete isolated from a Philippine sponge (Porifera)

The taxonomic status of a marine actinomycete isolated from the sponge Haliclona sp. collected from Cebu, Philippines, was established using both phenotypic and genotypic data. Strain SPE 10-1(T) exhibited chemotaxonomic and morphological characteristics that were consistent with those of members of the genus Saccharopolyspora. It showed a strict requirement for salt and is the first obligate marine bacterium of the genus Saccharopolyspora to be isolated. The principal isoprenoid quinone detected was MK-9(H(4)). The fatty acid pattern consisted mainly of terminally branched iso and anteiso fatty acids. The DNA G+C content was 72.6 mol%. Analysis of the 16S rRNA gene sequence supported affiliation of the strain with the genus Saccharopolyspora; the type strain of Saccharopolyspora gregorii was the closest phylogenetic relative (96 % sequence similarity). Sequence similarities of strain SPE 10-1(T) to other type strains of this genus were 93-95 %. It is proposed that strain SPE 10-1(T) should be classified in the genus Saccharopolyspora as a representative of Saccharopolyspora cebuensis sp. nov. The type strain of Saccharopolyspora cebuensis is SPE 10-1(T) (=DSM 45019(T)=CIP 109355(T))

Classical approach in quantum physics

The application of a classical approach to various quantum problems - the secular perturbation approach to quantization of a hydrogen atom in external fields and a helium atom, the adiabatic switching method for calculation of a semiclassical spectrum of hydrogen atom in crossed electric and magnetic fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's approach to Stark problem, long-lived excited states of a helium atom recently discovered with the help of Poincar$\acute{\mathrm{e}}$ section, inelastic transitions in slow and fast electron-atom and ion-atom collisions - is reviewed. Further, a classical representation in quantum theory is discussed. In this representation the quantum states are treating as an ensemble of classical states. This approach opens the way to an accurate description of the initial and final states in classical trajectory Monte Carlo (CTMC) method and a purely classical explanation of tunneling phenomenon. The general aspects of the structure of the semiclassical series such as renormgroup symmetry, criterion of accuracy and so on are reviewed as well. In conclusion, the relation between quantum theory, classical physics and measurement is discussed.Comment: This review paper was rejected from J.Phys.A with referee's comment "The author has made many worthwhile contributions to semiclassical physics, but this article does not meet the standard for a topical review"

Procedures of sensors deployment methodology on physical supports/platforms

The aim of task 2.3 is to define specific platform characteristics and identify deployment difficulties in order to determine the adequacy of sensors within specific platforms. In order to obtain the necessary information, two online questionnaires were realized. One questionnaire was created for sensor developers and one for those partners that will test the sensors at sea. The seven developers in COMMON SENSE have provided information on seven sensors: two for underwater noise – CEFAS and IOPAN; two for microplastics – IDRONAUT and LEITAT; one for an innovative piro and piezo resistive polymeric temperature and pressure – CSIC; one for heavy metal – CSIC; one for eutrophication sensor – DCU. Outside the scope of the questionnaire, FTM has proposed three sensors of which two for oil spill and one for heavy metals, realized in the framework of a previous EU project but that can be improved and tested with several platforms. This information is anyway incomplete because in most cases for the novel sensors which will be developed over the course of COMMON SENSE, the sensors cannot be clearly designed yet as the project only started a few months ago - and, consequently, technical characteristics cannot actually be perfectly defined. This produces some lag in the acquired information that will be solved in the near future. In the other questionnaire, partners-testers have provided information on eleven platforms. Outside the questionnaire, IOPAN has described two more platforms, one of which is a motorboat not previously listed in the DoW, and they have informed us that the oceanographic buoy in Gdansk Bay is not actually available. This is valid also for platforms from other partners where there were only preliminary contacts like for example for Aqualog and OBSEA Underwater observatory. In the following months, new information will be provided and questionnaires information updated. Then important characteristics have to be considered such as maintenance, energy autonomy, data transfer/storage and dimension of the sensors that are actually missing. Further updates of this report are therefore necessary in order to individuate the most suitable platforms to test each kind of sensor and then used at the end of 2014 when WP9 (Testing activities) will start. Objectives and rationale The objective of deliverable 2.2 is the definition of the characteristics and procedures of sensors deployment methodology on physical supports/platforms, possible needs and characteristics of the available platform. This is preparatory for the activities in other WPs and tasks: - for task 2.2 (New generation technologies), that will provide cost-effective sensors for large scale production through Deliverable 2.1 [month 10]; - for task 2.5 (Monitoring strategy) where sensitivity and stress tests of new sensors will be designed in order to establish confidence limits under different situations and certify the performance of the new instruments [Deliverable 2.5 at month 16]. - for WP9 (Field testing) starting at month 12 (October 2014) when the deployment of new sensors will be drawn and then realized

Ionization via Chaos Assisted Tunneling

A simple example of quantum transport in a classically chaotic system is studied. It consists in a single state lying on a regular island (a stable primary resonance island) which may tunnel into a chaotic sea and further escape to infinity via chaotic diffusion. The specific system is realistic : it is the hydrogen atom exposed to either linearly or circularly polarized microwaves. We show that the combination of tunneling followed by chaotic diffusion leads to peculiar statistical fluctuation properties of the energy and the ionization rate, especially to enhanced fluctuations compared to the purely chaotic case. An appropriate random matrix model, whose predictions are analytically derived, describes accurately these statistical properties.Comment: 30 pages, 11 figures, RevTeX and postscript, Physical Review E in pres

Holographic RG flow of the shear viscosity to entropy density ratio in strongly coupled anisotropic plasma

We study holographic RG flow of the shear viscosity tensor of anisotropic, strongly coupled N=4 super-Yang-Mills plasma by using its type IIB supergravity dual in anisotropic bulk spacetime. We find that the shear viscosity tensor has three independent components in the anisotropic bulk spacetime away from the boundary, and one of the components has a non-trivial RG flow while the other two have a trivial one. For the component of the shear viscosity tensor with non-trivial RG flow, we derive its RG flow equation, and solve the equation analytically to second order in the anisotropy parameter 'a'. We derive the RG equation using the equation of motion, holographic Wilsonian RG method, and Kubo's formula. All methods give the same result. Solving the equation, we find that the ratio of the component of the shear viscosity tensor to entropy density 'eta/s' flows from above '1/4pi' at the horizon (IR) to below '1/4pi' at the boundary (UV) where it violates the holographic shear viscosity (Kovtun-Son-Starinets) bound and where it agrees with the other longitudinal component.Comment: 17 pages, 2 figures, slight change on the title, more background material added, references added, accepted for publication in JHE

Doping the holographic Mott insulator

Mott insulators form because of strong electron repulsions, being at the heart of strongly correlated electron physics. Conventionally these are understood as classical "traffic jams" of electrons described by a short-ranged entangled product ground state. Exploiting the holographic duality, which maps the physics of densely entangled matter onto gravitational black hole physics, we show how Mott-insulators can be constructed departing from entangled non-Fermi liquid metallic states, such as the strange metals found in cuprate superconductors. These "entangled Mott insulators" have traits in common with the "classical" Mott insulators, such as the formation of Mott gap in the optical conductivity, super-exchange-like interactions, and form "stripes" when doped. They also exhibit new properties: the ordering wave vectors are detached from the number of electrons in the unit cell, and the DC resistivity diverges algebraically instead of exponentially as function of temperature. These results may shed light on the mysterious ordering phenomena observed in underdoped cuprates.Comment: 27 pages, 9 figures. Accepted in Nature Physic

Ionization of hydrogen and hydrogenic ions by antiprotons

Presented here is a description of the ionization of hydrogen and hydrogenic ions by antiproton-impact, based on very large scale numerical solutions of the time-dependent Schr\"odinger equation in three spatial dimensions and on analysis of the topology of the electronic eigenenergy surfaces in the plane of complex internuclear distance. Comparison is made with other theories and very recent measurements.Comment: RevTex document, 11 pages, 4 Postscript figures are available from the authors, in press Phys. Rev. Let

Field testing, validation and optimization report

The COMMON SENSE project has been designed and planned in order to meet the general and specific scientific and technical objectives mentioned in its Description of Work (page 77). As the overall strategy, the 11 work packages (WPs) of the work plan were grouped into 3 key phases: (1) RD basis for cost-effective sensor development , (2) Sensor development, sensor web platform and integration, and (3) Field testing. In the first two phases, partners involved in WP1 and WP2 have provided a general understanding and integrated basis for a cost effective sensors development. Within the following WPs 4 to 8 the new sensors were created and integrated into different identified platforms. During the third phase of field testing (WP9), partners have deployed precompetitive prototypes at chosen platforms (e.g. research vessels, oil platforms, buoys and submerged moorings, ocean racing yachts, drifting buoys). Starting from August 2015 (month 22; task 9.2), these platforms have allowed the partnership to test the adaptability and performance of the in-situ sensors and verify if the transmission of data is properly made, correcting deviations. In task 9.1 all stakeholders identified in WP2 have been contacted in order to agree upon a coordinated agenda for the field testing phase for each of the platforms. Field testing procedures (WP2) and deployment specificities, defined during sensor development in WPs 4 to 8, have been closely studied by all stakeholders involved in field testing activities in order for everyone to know their role, how to proceed and to provide themselves with the necessary material and equipment (e.g. transport of instruments). All this information have provided the basis for designing and coordinating field testing activities. Subsequently, the available new sensors have been tested since August 2015 till mid-October of the current year (2016) as part of task 9.2, following the indications defined in D9.1, such as the intercomparison of the new sensors with commercial ones, when possible. The availability of new sensors was quite different in time starting with the first tests in September and October 2015 on noise, nutrient and heavy metals sensors and closing with pCO2 in late September 2016. Sensors are technically fully described in the deliverables of WPs 3 to 8 and are here just mentioned where necessary. For further details, please consider those reports. Objectives and rationale The protocols prepared in D9.1 have been verified during the field testing activities of the innovative sensors on platforms. These can be summarized into 3 categories: (1) Research vessels (regular cruises); (2) Fixed platforms; (3) Ocean racing yachts. An exhaustive analysis of the different data obtained during field testing activities has been carried on in order to set possible optimization actions for prototypes design and performances. The data from each platform have been analyzed to verify limits and optimal installations or possible improvements. Finally a set of possible optimization actions has been defined. Data and observations collected during the course of field testing have been used to iteratively optimize the design and performance of the precompetitive prototypes