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Neji Khelifi 《Journal of Russian Laser Research》2008,29(3):274-287
Adiabatic and diabatic study for all the states dissociating below the ionic limit [i.e., Na (3s, 3p, 4s, 3d, 4p, 5s, 4d,
and 4f) + H (1s)] in 1Σ+ and 3Σ+ symmetries are presented. Adiabatic results are also reported for 1,3Π and 1,3Δ symmetries. Pseudo-potential, operatorial core-valence correlation, and full valence CI approaches combined with an efficient
diabatization procedure are used in these ab initio calculations. Our vibrational-level spacings and spectroscopic constants
are in good agreement with the available experimental data for the low-lying states. Diabatic potentials and dipole moments
are analyzed, revealing the strong imprint of the ionic state in the 1Σ+ adiabatic states. The hydrogen electron affinity correction was taken into account by the use of the efficient diabatization
method. This leads to a better agreement with the available experimental data. Experimental suggestions are also given for
the higher excited states based on their unusual behavior. 相似文献
3.
We determined and tried to understand the spectroscopic and structural properties of small LiAr and LiAr2 molecules within a simple model considering LiAr as a result of interaction between a valence electron and a LiAr+ molecular ion. Potential energy curves, spectroscopic constants, and vibrational levels corresponding to the Li(2s, 2p, 3s, and 3p)+Ar dissociation are reported for the LiAr molecule. The depth of the potential well for the X
2Σ+ ground state is found to be 50 cm−1 (the corresponding experimental value is (42.5±1.2) cm−1 [1]). R
e is determined to be 9.36 a.u. (the experimental value is 9.24 a.u.). For the first excited state A, R
e = 4.97 a.u. and D
e = 993cm −1 (the corresponding experimental values are 4.68 a.u. and (925−40) cm−1, respectively [1]). The spacing between the vibrational levels for the ground and first excited states is in very good agreement
with the experiment. For the ground state, the difference between our results and the data of the most recent experiment is
about 1 cm−1. The model has been extended to study the LiAr2 molecule in two forms (linear and triangular). We have determined the potential energy surfaces of the states dissociating
to Li(2s, 2p)+Ar2 and thus found the triangular form to be more stable as compared to the linear one. We have also calculated the transition
energy between the ground state and first excited states of this molecule. The emission spectrum of the Li(2s)+Ar2→Li(2p)+Ar2 transition in both forms redshifts as compared to the Li(2s)→Li(2p) atomic transition. 相似文献
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Mabrouk Khelifi Imen Mkaouar Faouzi Hlel Abdelhamid Ben Salah Ridha Zouari 《Ionics》2010,16(8):709-715
The crystal structure of (C5N2H7)4.HBi2Cl11 has been determined at room temperature by single crystal X-ray diffraction. The compound crystallizes in the triclinic system with Pī space group. The crystal structure consists of two asymmetric inequivalent molecules of 4-aminopyridinium and anionic HBi2Cl11 chains. The HBi2Cl11 anionic chains stacked along the a-axis are formed with Bi2Cl11 dimers connected to each other via hydrogen atoms. The crystal packing is stabilized with N–H...Cl hydrogen bonds connecting aminopyridinium units to the HBi2Cl11 anionic chains. The title compound exhibits an order–disorder phase transition at 338 K. The AC electrical conductivity properties of (C5N2H7)4.HBi2Cl11 compound have been investigated by means of impedance spectroscopy measurements over wide ranges of frequencies and temperatures, 200 Hz to 5 MHz and 303 to 418 K, respectively. Detailed analysis of the impedance spectrum suggests that the electrical properties of the material are strongly temperature dependent. The frequency-dependent conductivity data were fitted in the Jonscher's law: $ \sigma \left( \omega \right) = \sigma (0) + A{\omega^n} $ . The nature of variation of DC conductivity suggests Arrhenius type of electrical conductivity. 相似文献
6.
Christian Daveau Diane Manuel Douady Abdessatar Khelifi Anton Sushchenko 《Applicable analysis》2013,92(5):975-996
We consider the numerical solution, in a three-dimensional bounded domain, of the inverse problem for identifying the location of small electromagnetic imperfections in a medium with homogeneous background. Our numerical algorithm is based on the coupling of a discontinuous Galerkin method for the time-dependent Maxwell's equations, on the exact controllability method and on a Fourier inversion. Several numerical results are given with one and two imperfections and the robustness and accuracy of the numerical method used for the dynamic detection problem are shown. 相似文献
7.
Fadhila Ayari Ghada Manai Selma Khelifi Malika Trabelsi-Ayadi 《Journal of Saudi Chemical Society》2019,23(3):294-306
In this study, the adsorption removal of an anionic dye (Congo red) by a local bentonite before and after modification was studied. The modification of the bentonite was made by organophilisation using surfactant (HDTMA) and by pillaring process to obtain a bentonite with Ti pillars and with mixed pillars of Fe/Al. The various synthesized materials are characterized by different techniques such as DRX, MET, N2 adsorption-desorption, Zeta potential measurement. Results show the development of the texture and the structure of the bentonite after modification. The various adsorbents synthesized show an increase in the adsorption capacity of Congo Red compared to the initial bentonite. Adsorption isotherms are described by the Langmuir model in all cases except that for Ti pillared bentonite, the Freundlich model is more suitable. Pseudo-second order is better for describing the adsorption process. Also, regeneration of the adsorbent is approached in this study by photochemical way and the results show a total regeneration of the adsorbent. 相似文献
8.
We present pseudo-potential calculations of geometrical structures of stable isomers of LiAr
n
clusters with both an electronic ground state and excited states of the lithium atom. The Li atom is perturbed by argon atoms
in LiAr
n
clusters. Its electronic structure obtained as the eigenfunctions of a single-electron operator describing the electron in
the field of a Li+Ar
n
core, the Li+ and Ar atoms are replaced by pseudo-potentials. These pseudo-potentials include core-polarization operators to account for
the polarization and correlation of the inert core with the valence Lithium electron [J Chem Phys 116, 1839 1]. The geometry optimization of the ground and excited states of LiAr
n
(n = 1–12) clusters is carried out via the Basin-Hopping method of Wales et al. [J Phys Chem 101, 5111 2; J Chem Phys 285, 1368 3]. The geometries of the ground and ionic states of LiAr
n
clusters were used to determine the energy of the high excited states of the neutral LiAr
n
clusters. The variation of the excited state energies of LiAr
n
clusters as a function of the number of argon atoms shows an approximate Rydberg character, corresponding to the picture
of an excited electron surrounding an ionic cluster core, is already reached for the 3s state. The result of optical transitions calculations shows that the absorption spectral features are sensitive to isomer
structure. It is clearly the case for transitions close to the 2p levels of Li which are distorted by the cluster environment. 相似文献
9.
Elhadi Ait Dads Safoua Khelifi Mohsen Miraoui 《Mathematical Methods in the Applied Sciences》2020,43(17):10262-10275
In this paper, by developing important properties on the composition of functions with reflection, using some exponential dichotomy properties and an application of the fixed-point theorem, several new sufficient conditions for the existence and the uniqueness of an pseudo almost automorphic solutions with measure for some general-type reflection integro-differential equations. We suppose that the nonlinear part is measure pseudo almost automorphic and in which we distinguish the two constant and variable cases for the Lipschitz coefficients of the functions associated with this part. It is assumed that the linear part of the equation considered admits an exponential dichotomy. Finally, an application is given on the very interesting model of Markus and Yamabe. 相似文献
10.
Theoretical study of the electronic structure of LiNa and LiNa<Superscript>+</Superscript> molecules
Neji Khelifi Riadh Dardouri Omar Marzook Al-Dossary Brahim Oujia 《Journal of Russian Laser Research》2009,30(2):172-186
Adiabatic potential energy, spectroscopic constants, dipole moments, and vibrational levels of the lowest electronic states
of the alkali dimer LiNa molecule dissociating into Na (3s, 3p, 4s, 3d, and 4p) + Li (2s, 2p, 3s, and 3p) in 1,3Σ, 1,3Π, and 1,3Δ symmetries are presented. Adiabatic results are also reported for 2Σ, 2Π, and 2Δ electronic states of the molecular ion LiNa+ dissociating into Li (2s, 2p, 3s, and 3p) + Na+ and Li+ + Na(3s, 3p, 4s, 3d, and 4p). We use an ab initio approach involving a non-empirical pseudopotential for the Li (1s2) and Na (1s22s22p6) cores and core valence correlation correction. A very good agreement is obtained for some lowest states of the LiNa and
LiNa+ molecules for spectroscopic constants with the available theoretical works. The existence of numerous avoided crossings between
electronic states of 2Σ and 2Π symmetries is related to the charge transfer process between the two ionic systems Li+Na and LiNa+. 相似文献