Energy level analyses of even-parity J=1 and 2 Rydberg states of Sn I by multichannel quantum defect theory

This paper analyzes the energy levels along the even-parity J=1 and 2 Rydberg series of Sn I by multichannel quantum defect theory. A good agreement between theoretical and experimental energy levels was achieved. Below 59198 cm~(-1), a total of 85 and 23 new energy levels, respectively, in the J=1 and J=2 series, which cannot be measured previously by experiments, are predicted in this work. Based on the calculated admixture coefficients of each channel, interchannel interactions were discussed in detail. The results are helpful to understand the characteristics of configuration interaction among even-parity levels in Sn I.

State-to-state dynamics of elementary chemical reactions using Rydberg H-atom translational spectroscopy

In this review, a few examples of state-to-state dynamics studies of both unimolecular and bimolecular reactions using the H-atom Rydberg tagging TOF technique were presented. From the H2O photodissociation at 157 nm, a direction dissociation example is provided, while photodissociation of H2O at 121.6 has provided an excellent dynamical case of complicated, yet direct dissociation process through conical intersections. The studies of the O(D-1) + H-2 --> OH+H reaction has also been reviewed here. A prototype example of state-to-state dynamics of pure insertion chemical reaction is provided. Effect of the reagent rotational excitation and the isotope effect on the dynamics of this reaction have also been investigated. The detailed mechanism for abstraction channel in this reaction has also been closely studied. The experimental investigations of the simplest chemical reaction, the H-3 system, have also been described here. Through extensive collaborations between theory and experiment, the mechanism for forward scattering product at high collision energies for the H+HD reaction was clarified, which is attributed to a slow down mechanism on the top of a quantized barrier transition state. Oscillations in the product quantum state resolved different cross sections have also been observed in the H+D-2 reaction, and were attributed to the interference of adiabatic transition state pathways from detailed theoretical analysis. The results reviewed here clearly show the significant advances we have made in the studies of the state-to-state molecular reaction dynamics.

LIFETIMES OF RYDBERG LEVELS IN THE PERTURBED 6SNP P-1,3(1) SERIES OF YBI

Using two methods: (1) three-step excitation and (2) single UV photon excitation in an atomic beam with direct observation of the decay of the fluorescence light, we have measured the lifetimes of the Rydberg levels of YbI belonging to the perturbed series 6snp J = 1 levels. The measured values have been interpreted by the multichannel quantum defect theory (MQDT).

LIFETIMES OF RYDBERG LEVELS IN THE PERTURBED 6SNP 3P2 SERIES OF YTTERBIUM-I

Using three-step laser excitation in an atomic beam and a time-resolved spectroscopy technique, we measured both the lifetimes of the Rydberg levels of Yb I belonging to the perturbed series 6nsp 3P2 and the lifetimes of the perturbing 4f(13)5d(2)6s 3P2, 1D2 levels. An expected shortening has been observed for the lifetimes of those levels which are strongly mixed with the perturbers.

Quantum computation based on a quantum switch in cavity QED

A feasible scheme for constructing quantum logic gates is proposed on the basis of quantum switches in cavity QED. It is shown that the light field which is fed into the cavity due to the passage of an atom in a certain state can be used to manipulate the conditioned quantum logical gate. In our scheme, the quantum information is encoded in the states of Rydberg atoms and the cavity mode is not used as logical qubits or as a communicating "bus"; thus, the effect of atomic spontaneous emission can be neglected and the strict requirements for the cavity can be relaxed.

The Stark effect on excitons in a bilayer system

The Stark effect on excitons in a bilayer system is investigated theoretically within the framework of the effective-mass approximation. The calculations indicate that the energy of the excitons decreases as the value of the in-plane electric field F increases at a fixed value of the distance d between the layers. However, the energy of the excitons increases with d at a fixed value of F. In particular, it increases linearly at small values of d but increases as 1/d at large values. Therefore, it can be concluded that excitons in a bilayer system have a small binding energy equal to the absolute value of the excitonic energy at large d or small F. In addition, the radiative lifetime of heavy-hole excitons in this system is calculated and is found to be short at small values of both F and d. The radiative lifetime of heavy-hole excitons in a bilayer system can be increased by two orders by an in-plane electric field of 2 kV/cm when d is twice the excitonic Rydberg. (c) 2006 American Institute of Physics.