Rydberg field ionization

Several methods have been employed to measure the energy of this state in nonpolar liquids. The methods fall into three categories the change in work function of a metal when immersed in the liquid, photoionization, and field ionization. Of these, the latter, in which field ionization of high-lying Rydberg states is utilized to locate Fq, has in recent years provided what are considered to be the most accurate values of Fq in fluid Ar, Kr, and Xe. 

When the pulsed-field ionization signal of a single excited Rydberg peak is measured as a function of the delay time between the extraction field pulse... 

T. P. Softley The aims of ZEKE spectroscopy are conceptually different from the atomic pulsed-field ionization experiments that predate ZEKE. In the latter, the aim is always to observe and study the individual Rydberg states. In ZEKE spectroscopy the aim is to detect small batches of Rydberg states lying below successive vibration-rotation thresholds of the ion without specific interest in the individual Ryd-... 

Measurement of the survival probability of Rydberg molecules as a function of delay time for pulsed-field ionization. 

B. Kohler My question to T. Softley ties in to one of the major themes of the meeting, namely coherence. In your presentation you briefly mentioned that it may be important to consider an initially coherent superposition of states in the preparation step of experiments on highly excited Rydberg states. Several groups have now prepared coherent electronic wavepackets using picosecond (and shorter) pulses. Would this kind of an initial state be useful for any of the classes of pulsed-field ionization experiments that you have described ... 

Field ionization, which is of great practical importance in the study of Rydberg atoms, has been introduced implicitly in Figs. 6.2,6.6, and 6.7. We now consider it explicitly. The order of magnitude of the field required for ionization can be estimated using the method outlined in Chapter 1. The combined coulomb-Stark potential,... 

Because it can be efficient and selective, field ionization of Rydberg atoms has become a widely used tool.1 Often the field is applied as a pulse, with rise times of nanoseconds to microseconds,2"4 and to realize the potential of field ionization we need to understand what happens to the atoms as the pulsed field rises from zero to the ionizing field. In the previous chapter we discussed the ionization rates of Stark states in static fields. In this chapter we consider how atoms evolve from zero field states to the high field Stark states during the pulse. Since the evolution depends on the risetime of the pulse, it is impossible to describe all possible outcomes. Instead, we describe a few practically important limiting cases. 

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