Rydberg regime

There is no problem with the existence of the Rydberg regime. Its existence is guaranteed on the basis of the elementary independent particle model, an excellent approximation of the helium states in the Rydberg regime where n m. 

In this paper we examined quantum aspects of special classical configurations of two-electron atoms. In the doubly excited regime, we found quantum states of helium that are localized along ID periodic orbits of the classical system. A comparison of the decay rates of such states obtained in one, two and three dimensional ab initio calculations allows us to conclude that the dimension of the accessible configuration space does matter for the quantitative description of the autoionization process of doubly excited Rydberg states of helium. Whilst ID models can lead to dramatically false predictions for the decay rates, the planar model allows for a quantitatively reliable reproduction of the exact life times. 

M. Chergui Bubble formation is a consequence of the change in molecule-environment interactions. If the density of the gas is such that you probe, from the ground state, a distribution of distances for which this interaction is repulsive in the excited state, then you will form a bubble. The relevant regime of densities need not be very high since Rydberg states are extremely sensitive to the environment [for the case of NO, see Miladi et al., J. Mol. Spect. 55, 81 (1975) and 69, 260 (1978) Morikawa et al., J. Chem. Phys. 89, 2729 (1988) and Chergui et al., Chem. Phys. Lett. 216, 34 (1993)]. 

While the Na 19s — 18p, 19p transfer rate is an excellent illustration of the validity of Eq. (5.16) for co < kT, the photoionization of Rydberg atoms of n = 20 by black body radiation is a test of the regime a> kT, and this regime has been explored by Spencer et al 21 Specifically, they measured the relative rates for... 

This result was first derived in an elegant manner by Fermi.2 It can also be derived in a pedestrian way using the form of the interaction given by Eq. (11.17). The derivation is implicitly statistical, in that the motion of the perturber is ignored, which at first seems to imply that it should not match the results of an impact theory. However, we are only ignoring the thermal motion of the perturber relative to the electron motion. It is still true that the Rydberg electron interacts with one perturber at a time, thus the requirement of the impact regime is met. 

For completeness, we also present the method used by Fermi2 to calculate the shift due to the Rydberg ion polarization interaction in the statistical regime. If there are rare gas atoms located at points R the energy shift of a single Rydberg ion is given by8... 

In the experiments with Rydberg atoms it is very difficult to observe radiatively assisted collisions with cross sections more than a factor of 10 smaller than the resonant collision cross sections, so the deviations from Eq. (15.29) are not apparent. However, in other contexts, such as laser assisted collisions, this limitation does not apply, and it is interesting to consider how the above description passes over into the weak field regime, in which Jm(KEmv//oj) is small. If we restrict the integration in Eq. (15.27) to the large r region of space, in which the approximations we have used are valid, we can rewrite Eq. (15.27) as... 

Fig. 10.11. Qualitative sketch (because of graphical reasons not to scale) of the repetitive sequence of three different dynamical regimes in the helium atom Ericson, Wigner and Rydberg. The Ericson and the Wigner regimes are manifestations of chaos in the helium atom.

Reaction 16 was first laser induced by Happer and co-workers in a cell experiment under a multi-collision regime, which allowed, spectacularly, the product CsH to condense as powder, the so-called laser snow [144]. The dynamic picture of this reaction has emerged from a series of studies by Vetter and co-workers using a crossed-beam machine where cesium was excited to both the levels 6d [145] and 7p P [146-150]. The most interesting result concerns the reaction dynamics of cesium in the (7p Pi/2) level, which was interpreted after ah initio potential energy surface, semi-classical and quantal dynamics calculations [151 153]. The reaction of cesium in the 8p P and 9p P Rydberg levels with hydrogen molecules has also been studied [154]. 

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