The Cs2 ground electronic state by Fourier transform spectroscopy:: Dispersion coefficients

This study presents the derivation of an accurate potential energy curve for the ground electronic state of the Cs-2 molecule. High resolution laser induced emission spectra data involving vibrational levels of the ground X (1)Sigma(g)(+) state up to v(')=135 (16 900 wave numbers) have been determined. The ground state potential energy curve is constructed by combining the inverted perturbation approach for internuclear distances up to 11 A, with an analytical expression for longer internuclear distances. This potential curve allows an improved derivation of the dissociation energy and of the Coulombic parameters governing the Cs(6s)+Cs(6s) interaction in the electronic ground state, compared with values derived either by calculations or by recent photoassociative spectroscopy measurements. The main constants are C-6=6836 (+/-100) a.u.=32.945 (+/-0.49)x10(6) cm(-1) A(6), and D-e=3649.88 (+/-0.45) cm(-1). (C) 2002 American Institute of Physics.