APPLICATION OF THE 'MLR' DIRECT POTENTIAL FITTING (DPF) METHOD FOR THE $X^{1}\Sigma_g^+$ STATE OF Cs$_2$

Abstract

A set of 16544 $A^{1}\Sigma_u^+$ - $X^{1}\Sigma_g^+$ fluorescence line positions, 5155 (2002).} with a measurement precision of 0.001 cm$^{-1}$, and which samples ground state levels up to $\upsilon^{\prime\prime}$ = 135 lying about 28 cm$^{-1}$ below the dissociation limit, has been employed in least-squares fits using the MLR direct potential fitting approach , 663 (2007).}. As well as the extended MLR model employed recently for Li$_2$, a further extension employing three \textit{y$_i$}-variables leads to an optimum model for Cs$_2$ that ensures a realistic extrapolation into the long-range region in accord with the theoretical dispersion constants.