XVIth International Workshop on
Quantum Systems in
Chemistry and Physics
QSCP logo Abstract
 Main | Registration | Abstract Submission | List of Registrants | List of Abstracts | Program 
Accommodation | Location and Access | Previous Workshops | ISTCP-VII | Photos
Oral presentations only. Posters only. Show all.

Electronic Absorption Spectra of the RgAr (Rg=Cs, Rb) Van der Waals Complexes
J. Dhiflaouia, H. Berrichea,b and M. C. Heavenc
aLaboratoire de Physique et Chimie des Interfaces, Département de Physique, Facultée des Sciences de Monastir, Avenue de l’Environnement, 5019 Monastir, Tunisie)
bPhysics Department, Faculty of Science, King Khalid University, P. O. Box 9004,
Abha, Saudi Arabia.
cChemistry Department, Emory University, Atlanta, USA

*E-mail address: hamid.berriche@fsm.rnu.tn, hamidberriche@yahoo.fr
The potential energy curves of the ground state and many excited states of the RbAr and CsAr van der Waals complexes have been determined using [Rb+], [Cs+] and [e-Ar] pseudopotentials with the inclusion of core polarization operators on both atoms. This has reduced the number of active electrons of the RgAr (Rg=Rb and Cs) system to only one valence electron, permitting the use of large basis sets for the Rb, Cs and Ar atoms. Potential energy curves of the ground state and many excited states have been calculated at the SCF level. The core-core interactions for Rg+Ar are included using the accurate CCSD potential of Hickling et al [Hickling, H.; Viehland, L.; Shepherd, D.; Soldan, P.; Lee, E.; Wright, T. Phys. Chem. Chem. Phys. 2004, 6, 4233]. Spectroscopic constants for the ground and excited states of RgAr are derived and compared with the available theoretical and experimental results. Furthermore, we have predicted the X2Σ+---A2Π1/2, X2Σ+---A2Π3/2 and X2Σ+--B2Σ1/2+absorption spectra.
The potential energy surface of Li2+(X2Σg+) alkali dimer colliding with the Xe atom
S. Saidi1, C. Ghanmi1, F. Hassen2 and H. Berriche*1,3
1Laboratoire de Physique et Chimie des Interfaces, Département de Physique, Faculté des Sciences de Monastir, Avenue de l’Environnement, 5019 Monastir, Tunisia.
2Laboratoire de Physique des Semiconducteurs et des Composants Electroniques, Faculté des Sciences, Avenue de l’environnement, 5019 Monastir, Tunisie
3Physics Department, College of Science, King Khalid University, P. O. Box 9004, Abha, Saudi Arabia

*Corresponding author: hamid.berriche@fsm.rnu.tn, hamidberriche@yahoo.fr
The potential energy surface describing the collision between Li2+(X2Σg+) alkali dimer and the Xenon atom have been calculated for the equilibrium distance of the Li2+(X2Σg+) and for an extensive range of the two Jacobi coordinates, R and γ. We have used an ab initio approach based on non-empirical pseudopotential and a parametrized l-dependent polarization potential [1]. The core-core interactions for Li+Xe is included using the (CCSD(T)) accurate potential of Lozeille et al [2]. This numerical potential is interpolated using the analytical form of Tang and Toennies [3] for a better description of the interactions at intermediate and large distances between Li+ and Xe. This technique has reduced the number of active electrons of Li2+(X2Σg+)-Xe system to only one active electron. The Three-Body interactions are also considered in this calculation and an analytical fitting of the potential energy surface has been realized. To our knowledge, there are neither experimental nor theoretical studies on the collision between the Li2+(X2Σg+) alkali ionic molecule and the Xenon atom. Therefore, our results are presented here for the first time. In addition the analytical potential energy surface will be used to investigate solvation of Li2+ ionic alkali molecule in Xenon small clusters.

References
[1] Ph. Durand and J. C. Barthelat, theorit. Chim. Acta. 38 (1979) 283.
[2] Lozeille et al, Phys. Chem. Chem. Phys. 4 (2002) 3601)
[3] K. T. Tang and J. P. Toennies, J. Chem. Phys. 80 (1984) 3726.
Solvation of Li2+(X2Σg+) in small Xen clusters: structure and stability
S. Saidia, C. Ghanmia, F. Hassenb and H. Berriche*a,c
aLaboratoire de Physique et Chimie des Interfaces, Faculté des sciences, Université de de Monastir, Avenue de l’Environnement, 5019 Monastir, Tunisie
bLaboratoire de Physique des Semiconducteurs et des Composants Electroniques, Faculté des Sciences, Avenue de l’environnement, 5019 Monastir, Tunisie
cPhysics Department, College of Science, King Khalid University, P. O. B. 9004, Abha, Saudi Arabia

*E-mail address: hamidberriche@yahoo.fr
The structure and geometries of the small Li2+(X2Σg+)Xen clusters taken in different geometries with special symmetry groups, are examined. A one-electron pseudopotential approach is used to generate the potential energy surface of the Li2+-Xe triatomic system for a fixed distance between the two Li alkali atoms (the Li2+ equilibrium distance) and for different angles and distances between the Xenon and the Li2+ center of mass. In this approach, the effect of the Li+ core and the electron-Xe interactions are replaced by effective potentials. This has permitted to reduce the number of active electrons of the triatomic system to only one valence electron. In addition, the Li2+Xe interactions are introduced using an analytical form to describe the collision between the alkali ionic dimer and the Xe atom. However, a Lennard-Jones form is used for the Xe-Xe interactions and then included in the total potential energy surface describing the Li2+-Xen cluster. The optimized and stable geometries are performed using the Monte-Carlo Bassin Hoping method. This study has shown that the optimal structures correspond to those where Xenon atoms are aggregated on one or both ends of Li2+ dimer.

Key words: Pseudopotential, Microsolvation of clusters, Monte-Carlo, Structure,


 Main | Registration | Abstract Submission | List of Registrants | List of Abstracts | Program 
Accommodation | Location and Access | Previous Workshops | ISTCP-VII | Photos