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Ajili Y.,University Paris Est Creteil | Ben Abdallah D.,Riyadh Corporation of Technology | Mogren Al-Mogren M.,King Saud University | Francisco J.S.,Purdue University | Hochlaf M.,University Paris Est Creteil
Monthly Notices of the Royal Astronomical Society | Year: 2016

Three-dimensional potential energy surface (3D-PES) of the HNS-He interacting system in Jacobi coordinates is mapped using high-level ab initio theory. These computations are performed at the explicitly correlated coupled cluster method with single, double and perturbative triple excitations (CCSD(T)-F12) in conjunction with the augmented correlation-consistent aug-cc-pVTZ basis set. The 3D-PES is incorporated into quantum dynamical computations to treat the nuclear motions, where HNS is considered as a rigid rotator colliding with He. Cross-sections for transitions among the first twenty nine rotational levels of HNS (up to jKaKc = 92,8) are calculated using the quantum exact close-coupling method for total energies <1000 cm-1 and using the coupled state approximation for higher energies. Collisional rate constants for temperatures ranging from 5 to 200 K are deduced. A clear propensity rule in favour of Δj = -2 rotational transitions is observed. These rate coefficients are of great importance for the detection of HNS in interstellar medium. © 2016 The Authors.


Almenia S.,King Saud University | Mogren Al Mogren M.,King Saud University | Ben Abdallah D.,Riyadh Corporation of Technology | Linguerri R.,University Paris Est Creteil | Hochlaf M.,University Paris Est Creteil
Chemical Physics Letters | Year: 2016

We investigate VO2+ and VO3+ ions theoretically. The electronic computations are performed using multi reference configuration interaction approaches in conjunction with the aug-cc-pV5Z basis set. VO2+ potential possesses a Morse-like shape instead of the common volcanic shape since both the charge retaining (V2+ + O) and charge separating (V+ + O+) dissociation channels are almost coinciding in energy. Its intense blue color is due to the A2Π-X2Δ transition. We predict VO3+ as metastable. For bound states, we derived a set of accurate spectroscopic parameters. We estimate the adiabatic double and triple ionization energies of VO to be 22.5 eV and 50.9 eV. © 2016 Elsevier B.V. All rights reserved.


Ajili Y.,University Paris Est Creteil | Ben Abdallah D.,Riyadh Corporation of Technology | Mogren Al-Mogren M.,King Saud University | Lique F.,CNRS Laboratory of Waves and Complex Media | And 2 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2016

The intermonomer three-dimensional potential-energy surface (3D PES) of the thiazyl-hydride-helium (HSN-He) weakly bound molecular system is generated using the explicitly correlated coupled-cluster method with single, double, and perturbative triple excitations. The 3D PES is mapped in Jacobi coordinates. This potential-energy surface shows a unique potential well at planar configurations. The depth of this potential is 74.4cm-1. This 3D PES is incorporated into a close-coupling and coupled-states quantum dynamical treatment of nuclear motions to deduce the rotational (de-)excitation of HSN by He for energies up to 1400cm-1. After averaging over a Maxwell-Boltzmann distribution, the collisional rate coefficients are derived for temperatures ranging from 5 to 200 K. These data are essential for the identification of HSN molecules in astrophysical media. A comparison between thionitrosyl-hydride - He and HSN-He is performed. © 2016 American Physical Society.


Mogren Al Mogren M.,King Saud University | Ben Abdallah D.,University of Tunis | Ben Abdallah D.,Riyadh Corporation of Technology | Hochlaf M.,University Paris Est Creteil
Chemical Physics | Year: 2015

Using multi reference configuration interaction methodology in connection with a large basis set, we show that GeO2+ is a metastable species either in the ground or in the electronically excited states. This confirms the observation of this dication in gas phase by mass spectrometry. In addition, we derived a set of accurate spectroscopic terms for GeO2+ bound states. At the MRCI/aug-cc-pV5Z level of theory, the adiabatic double ionization energy of GeO is computed to be ∼28.93 eV. © 2014 Elsevier B.V. All rights reserved.


Najar F.,Tunis el Manar University | Ben Abdallah D.,Tunis el Manar University | Ben Abdallah D.,Riyadh Corporation of Technology | Jaidane N.,Tunis el Manar University
Chemical Physics Letters | Year: 2014

Adiabatic and diabatic potential energy surfaces (PESs) of the ground and the first excited electronic states for the interaction of C2(X 1Σg +,a3Πu) +H(2S) system have been computed from the ab initio multi-reference configuration interaction wave functions including Davidson correction (MRCI + Q), using the augmented correlation-consistent valence quadruple-zeta (aug-cc-pVQZ) basis set of Dunning. Mixing angle and coupling potential have been calculated for all selected ab initio geometries. The C2 bond length was fixed at the experimental equilibrium distance re=2.348 bohr of C2(XX1Σg +) state. Quantum mechanical coupled states rotational dynamics application has been done on the ground adiabatic and diabatic PESs. © 2014 Elsevier B.V. All rights reserved.

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