Chemical hardness as a possible diagnostic of the chaotic dynamics of Rydberg atoms in an external field

The possible signature of chaos in Rydberg atoms has been studied in terms of the dynamic profiles of the chemical hardness (eta), polarizability (alp ha), and uncertainty product (V-ps). A hydrogen atom in the electronic grou nd state (n = 1) and in an excited electronic state (n = 15) behaves differ ently when placed in both one- and two-color laser pulses. Temporal evoluti on of eta, alpha, and V-ps for these two cases (n = 1 and n = 15) show mark ed differences. It appears that a larger V-ps and a smaller eta value signa l a chaotic behavior.