A theoretical investigation of the diatomic dication SeO(2+) in the gas phase

International audienceThe present study was initiated by the recent observation of the novel molecular species SeO(2+) in the gas phase by Franzreb and Williams at Arizona State University. Here we report a very detailed theoretical investigation of the low-lying electronic states of SeO(2+). Our results show that the potential energy surfaces of the dicationic electronic states have high potential barriers with respect to dissociation, so this dication can exist in the gas phase as a long-lived metastable molecule. The potential energy curves are used to predict the double photoionization spectrum of SeO and to derive a set of spectroscopic parameters for the bound states of SeO(2+). (C) 2011 Elsevier B.V. All rights reserved

Spectroscopy and metastability of BeO+

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Theoretical spectroscopy and metastability of BeS and its cation

International audienceMulticonfiguration self-consistent field and multiconfiguration reference interaction including the Davidson's correction techniques were employed to calculate the potential energy curves (PECs) of the BeS/BeS+ electronic states correlating to the 4/5 lowest dissociation limits. After nuclear motion treatment, we deduced reliable spectroscopic data for the neutral and cationic bound states. For BeS, the transition moments and spin-orbit couplings were also evaluated and used later with the PECs to deduce the rovibronic transition probabilities and the radiative lifetimes in the low-lying states, and to investigate the unimolecular decomposition processes of BeS (X(1)Sigma(+), A(1)Pi, (3)Sigma(+) and B(1)Sigma(+)) leading to Be((1)S(g)) + S((3)P(g)). The prominent mechanism is a spin-orbit induced predissociation via the repulsive BeS(1(3)Sigma) state. Finally, we give the single ionization spectrum of BeS (X(1)Sigma(+)) populating the BeS(+) (X(2)Pi, 1(2)Sigma, 1(2)Sigma(+), 1(2)Sigma(+), 2(2)Sigma(+), 2(2)Pi and 3(2)Pi) electronic states. The adiabatic ionisation energy of BeS is estimated to be similar to 9.15 eV. (C) 2010 Published by Elsevier B. V

Calculation of the photo-ionisation cross sections and radiative recombination rate coefficients for N2, N2+, CO and CO+ molecules

International audienc

Calcul des sections efficaces de photo-ionisation et des taux de recombinaison radiative pour les molécules CO et CO+

National audienc

Thermodynamic properties and transport coefficients calculation for two-temperature air – methane plasma

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Calculation of Photo-Ionisation Cross Sections and Radiative Recombination Rate Coefficients for CO and CO+ Molecules

International audienceA method based upon the weighted total cross section (WTCS) theory is proposed to calculate the photo-ionisation cross sections and the radiative recombination rate coefficients between the fundamental level of CO and the main electronic states of its corresponding ion. Total photo-ionisation cross sections and radiative recombination rate coefficients are determined from the calculation of elementary vibrational photo-ionisation cross sections. Transitions between CO+(X, A and B) and CO(X) are considered. Total photo-ionisation cross sections and recombination coefficients are computed in the temperature interval 500-15000 K

State-to-state dissociation photoionization of molecular nitrogen : the full story

N2 is a major constituent of Earth and planetary atmospheres. First, evidenced in 1952, the dissociative photoionization of molecular nitrogen, N2, plays an important role in the species abundance, out of equilibrium evolution, and chemical reactivity of diverse media including upper atmospheres (the so-called ionospheres) and plasma. Many scenarios were proposed for rationalizing the dissociative ionization mechanisms and exit channels, which are reviewed here, mainly involving the N2 + (C2Σu +, v+) vibrational levels state-to-state dynamics on which we focus. We show, however, that previous studies are not comprehensive enough for fully shedding light on the complex undergoing processes. As a complementary global work, we used state-of-the-art quantum chemistry, time dependent and independent theoretical approaches associated to advanced experimental techniques to study the unimolecular decomposition of the N2 + ions forming the N+ + N products. In addition to the already suggested spin-orbit-induced predissociation of the cationic C2Σu + state, we documented a new mechanism based on vibronic coupling and tunneling dissociation. Besides, the quantum processes highlighted here should be also in action in the dynamics of electronically excited larger molecular systems involved in physical and chemical phenomena in plasma and in various natural environments on Earth and beyond

Enhanced SPR Sensitivity with Nano-Micro-Ribbon Grating—an Exhaustive Simulation Mapping

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