Role of Core Interactions and External Perturbations in the Autoionization of Xe

Abstract

In a recent paper (Vrakking, M. J. J.; Lee, Y. T.; J. Chem. Phys. 1995, 102, 8833) we reported that autoionization rates of Xe Rydberg states converging on the 2P1/2 upper spin orbit state of Xe+ strongly depend on the presence of dc electric fields and surrounding ions. In the current paper, we present theoretical calculations that illustrate that the observed electric field dependence of the autoionization rates is influenced by the existence of short-range Rydberg electron−core interactions. In the presence of dc electric fields the autoionization rates decrease as a result of orbital angular momentum mixing. In the case of the ns‘[1/2]1 series, mixing with the high-l manifold is mediated by short-range interactions with the rapidly autoionizing nd‘[3/2]1 series. As a result, effective l-mixing takes place at substantially lower electric field strengths than would otherwise be the case. The experimental results of the dc electric field dependence of Xe pulsed field ionization (PFI) signals are compared with the theory, and predictions are made for sub-nanosecond time-resolved ionization experiments.

Atomic photoionization processes under magnification

“…Since the quantum defects for p -and d-type orbitals are large in xenon, Stark levels repel each other very strongly near the numerous crossings that occur beyond the Inglis-Teller limit, resulting in a significant loss of regularity in the spectrum. As a result, although visual inspection suggests the presence of a number of overlapping Stark manifolds with principal quantum numbers in the range between 25 and 30, we have been unable to connect the observed levels with positions based on the calculation of a Stark map using an effective Hamiltonian approach [27]. Nevertheless, the observation of resolved continuum Stark states does allow us to investigate to what extent the observation of direct and indirect trajectories-as discussed in the previous section-is connected to the excitation of continuum Stark resonances by the laser.…”

Stabilization of predissociating nitric oxide Rydberg molecules using microwave and radio-frequency fields

“…The study of molecular Rydberg states is often complicated by a nonradiative decay mechanism not present in atoms, namely predissociation; for example, np Rydberg states approaching the first ionization limit of NO decay into N and O atoms. In this case, the 50p predissociation lifetime is estimated to be 0.4 ns, 1 five orders of magnitude shorter than the radiative lifetime of the 50p state of hydrogen, which is 23 s. 2 Since both predissociation and radiative decay rates obey a n Ϫ3 scaling law, one can extend the lifetimes of Rydberg states simply by going to higher n. However, doing so introduces an increased sensitivity to the stray electric fields that are unavoidable in any experimental apparatus. A reflection of this sensitivity at high n is the significant lifetime lengthening of optically accessible Rydberg states that is often observed due to stray-field Stark mixing with longerlived high-l states.…”

Millimeter-wave spectroscopy and multichannel quantum-defect-theory analysis of high Rydberg states of xenon: The hyperfine structure ofXe129+andSchäfer1, Raunhardt2, Merkt3 2010Phys. Rev. A

“…Whereas * merkt@xuv.phys.chem.ethz.ch the study of the hyperfine structure of the bound Rydberg states of krypton [6] covered only odd-parity states [the penetrating s ( = 0) and d ( = 2) Rydberg series with large quantum defects δ > 1], this study includes even-parity p ( = 1) and f ( = 3) levels, of which the f states exhibit nonpenetrating character with small quantum defects (0.02 δ 0.06). The new high-resolution millimeter-wave data enable us to improve the existing sets of MQDT data on xenon [43,[57][58][59][60][61][62][63][64][65].…”