Wave-packet reconstruction in a two-electron atom via impulsive isolated core excitation

In a two-electron atom, autoionization from an impulsive isolated core exci tation is a sensitive probe of a Rydberg electronic wave packet. This probe via the electron-electron correlation allows a quantum measurement of the wave function to be made. In addition to this capability, the measurement p rocess has the advantage that it is independent of the excitation process. An analytical formula describes this probe. This formula is used in conjunc tion with a nonlinear least-squares algorithm to reconstruct the wave funct ion of this wave packet. The algorithm is relatively insensitive to noise. With 20% added Gaussian noise, the algorithm can still reproduce the amplit udes and phases of the wave function. [S1050-2947(99)50112-1].