Simulations for x-ray imaging of wave packet dynamics*

Previous work on imaging wave packet dynamics with x-ray scattering revealed that the scattering patterns deviate substantially from the notion of instantaneous momentum density of the wave packet. Here it is shown that when the final state of the scattered electron and the scattered photon momentum are measured simultaneously, the scattering probability is found to be proportional to the modulus square of the Fourier transform of the instantaneous spatial wave function weighted by the final state of the electron. Several cases for the choice of final state of the electron are explored. First, the case where the final state can be measured up to a given principal quantum number n and orbital angular momentum l are presented. Next, the case where the final states can only be determined up to a given energy is discussed. Finally, the case of a wave packet consisting of a large amount of a known stationary state and a small amount of an unknown stationary state is examined and the scattering profile is used to determine the properties of the unknown state in the wave packet.