Rydberg states highly excited

Let us discuss briefly the peculiarities of the excited states. Highly excited (Rydberg) states form a separate class of excited states. Experimentally, using, for example, selective laser radiation, it is possible to excite one electron to the states described by very high n values. Rydberg states of atoms are observed in interstellar space. Rydberg atoms possess a number of pecularities their sizes may be very large, comparable to the size of... 

Seen from the point of view of ultra-violet spectroscopy, the situation of aromatic P-, S-, As- and Se-compounds is far more indeterminate than in the t5q)ical oxo and fluoro complexes of the same elements in high oxidation states. Thus, gaseous SFs does not have absorption bands before 95 kK 64) and it is by no means certain that the excited states of these bands involve 3d-orbitals. In many ways, it looks much more as a 4s-like Rydberg state of the whole molecule. 

By using a full panoply of theory—time-dependent density functional theory and CASSCF and CASMP2 ab initio methods—the states and potential-energy surface features associated with the dynamics were uncovered. The high-energy excitation of acetone gives several excited Rydberg states that reach the S2( , 3i) surface in... 

High Rydberg states were found, however, to have a very important property [11]. Rydberg states with quantum numbers n = 100,. .., 200, just 1-2 cm-1 below the respective level of the free ions, have recently been discovered to be surprisingly long-lived, typically some 50 jts [11, 12], whereas some 10 ns would have been anticipated [13]. If now the laser excitation... 

The other source of congestion is due to the molecular core. It is most readily discussed using the inverse Bom-Oppenheimer point of view to define the zero-order quantum numbers. Here each state of the ionic core has its very own series of high Rydberg states. The physical reality of this approximation is the observation [36,43] of the long-time stable ZEKE states not just below the lowest ionization threshold but also just below the threshold of ionization processes that leave an excited ionic core. Indeed, it is for this very reason that ZEKE spectroscopy is useful for the spectroscopy of ions (or for such neutrals that are produced by ionization of negative ions... 

There can be a difference between the dissociation of polyatomic molecules and delayed ionization in the nature of the initial excitation. In ZEKE spectroscopy the state that is optically accessed (typically via an intermediate resonantly excited state) is a high Rydberg state, that is a state where most of the available energy is electronic excitation. Such a state is typically directly coupled to the continuum and can promptly ionize, unlike the typical preparation process in a unimolecular dissociation where the state initially accessed does not have much of its energy already along the reaction coordinate. It is quite possible however to observe delayed ionization in molecules that have acquired their energy by other means so that the difference, while certainly important is not one of principle. 

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