Rydberg electron wavepacket dymanics in atoms and molecules

Abstract

The generation and detection of Rydberg electron wavepackets using picosecond lasers is discussed with reference to the observation of the dynamics of spin-orbit autoionization in Xe. A multiphoton (nanosecond + picosecond) excitation scheme is employed with two-photon phase-sensitive detection, based on the observation of Ramsey interference fringes. To complement the experiment, time-dependent multichannel quantum-defect theory (TD-MQDT) calculations have been developed to investigate the dynamics of a spin-orbit autoionizing Rydberg wavepacket in Ar. The time-dependent partial photoionization cross-sections reveal interesting interference patterns in the recurrence spectra which are accounted for in terms of the quantum defects of the autoionizing channels. Finally, the rovibrational and rotational autoionization dynamics of a Rydberg wavepacket in H 2 are investigated using TD-MQDT. It is demonstrated that, in the time-domain, the configuration interaction between rotational channels can be described quantitatively in terms of an interaction time. In contrast to the rovibrational autoionization lifetime, which is determined by the classical orbit period (∝ n 3 ), the rotational autoionization lifetime is determined by the kinetic energy of the electron wavepacket following collision with the ion core.

High resolution metrology of autoionizing states through Raman interferences

“…In the fields of femtosecond and attosecond science [1,2] photoelectron wavepacket interferometry is a well established technique for wavepacket metrology [3,4,5]. A complete characterization of an excited wave packet can be used to probe strong field effects [6,7], autoionization dynamics [8,9,10], and molecular processes [11]. In these pump-probe experiments, one first prepares the excited state wavepacket using a broadband, femtosecond or attosecond pump pulse, followed by a sufficiently broad band ionizing probe pulse.…”

Raman interferometry between autoionizing states to probe ultrafast wavepacket dynamics with high spectral resolution

“…Photoelectron wavepacket interferometry has been extensively applied to probe the electronic properties of atoms and molecules, to characterize the amplitudes and phases of constituent wavefunctions [1][2][3][4][5][6], and probe the strong field dynamics [7,8], autoionization [9][10][11], correlated electron dynamics [12][13][14], and molecular dynamics [15]. Typically, a bound atomic or molecular wavepacket can be prepared by exciting the system with a broadband femtosecond or attosecond pulse, followed by a delayed ionizing probe light pulse which interferes various components of the wavepacket in the continuum.…”