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The tunneling between double wells of atom in crossed electromagnetic fields is investigated by a one-dimensional Hamiltonian model. The crossed fields induced outer well is apart from the nuclear origin and it is very difficult to access by means of spectroscopy but it will be possible if there exists the tunneling of the electron between the outer well and the Coulomb potential predominated well at the nuclear origin. A one-dimensional quantum calculation with B-spline basis has been performed for hydrogen atom in crossed fields accessible in our laboratory, at B = 0.8 T and F = -220 V.cm(-1). The calculation shows that the wavefunctions of some excited states close to the Stark saddle point in the outer well extend over to the Coulomb potential well, making it possible to penetrate the quantum information of the outer well. However, the tunneling rate is very small and the spectral measurement of the transitions from the ground state should be of a high resolution and high sensitivity.

A robust time-dependent approach to the high-resolution photoabsorption spectrum of Rydberg atoms in magnetic fields is presented. Traditionally we have to numerically diagonalize a huge matrix to solve the eigen-problem and then to obtain the spectral information. This matrix operation requires high-speed computers with large memories. Alternatively we present a unitary but very easily parallelized time-evolution method in an inexpensive way, which is very accurate and stable even in long-time scale evolution. With this method, we perform the spectral calculation of hydrogen atom in magnetic field, which agrees well with the experimental observation. It can be extended to study the dynamics of Rydberg atoms in more complicated cases such as in combined electric and magnetic fields.

The stability of the complex-rotation method in B-spline basis for a simple atomic resonant scattering problem in free field is investigated. The numerical calculation shows that this method has a feature that the solution will not change in a wide range of rotation angle theta. Our determined scattering resonant energies and widths exactly coincide with the popularly accepted values. A new resonance is identified numerically although it is very broad. The norm of the complex eigenvalue, vertical bar E vertical bar, is proposed to investigate and to evaluate the stability of the obtained complex eigenvalues.

This paper has studied the barium spectra in external magnetic and electric fields on the recently-built system based on a super-conducting solenoid with high stability of better than I Gauss. Firstly, we compared the spectra in a high pure magnetic field of B = 4.00000 T for different polarized laser, (sigma(+) and (sigma(-). We prove that after a proper shift, the (sigma(+) and sigma(-) spectra are completely identical. We also investigated the dependence of the spectral feature in the high magnetic field on an additionally applied crossing electric field. Along with the increase of the electric field, there is an energy shift for every spectral line. Based on a transformative Hamiltonian, we explained this energy shift well.

A global analysis of all available and identified spectra of the PO2 radical has been performed. In this analysis, the infrared spectra of the nu(3) band, the microwave and far infrared laser magnetic resonance transitions in the ground state are fitted simultaneously to the effective Hamiltonian for asymmetric top molecules. Since the analysis absorbs reliable experimental data extensively, it bears the most precise and most complete set of molecular constants for PO2. These molecular constants can, be used to reproduce the spectra of PO2 accurately. Attention is also paid to the similarity and difference between PO2 and NO2.

Based on the global analysis of all available and reliable data for isotopic species 14NmO(m=16,17,18), the 14N16O rovibrational spectral lines are calculated with very high accuracy and completely agree with previous results. These lines with relative intensities can be achieved as an infrared frequency standard in the spectral range 1600-5600 cm-1. The calculated rovibrational transitions of 14NmO(m=17,18) have the same accuracy as that for 14N16O although their data are rare due to their small natural abundance.

With time-of-flight and electric field ionization detection technique, we investigate the motional Stark effect for highly excited Rydberg barium in high magnetic field and its active cancellation experimentally. In the experiment, the atom beam is aligned at a small angle of 15 degrees with respect to the magnetic field. The motional Stark effect cancellation is demonstrated on two sets of circularly polarized spectra in static magnetic field B = 1.00000 Tesla and B = 1.70000 Tesla, respectively, although the effect is very small (similar to 3.5 Vcm(-1)) in our apparatus configuration.

High order centrifugal distortion terms have been derived and added to the effective Hamiltonian of asymmetric top molecules. Based on this Hamiltonian, a program in Fortran 77 has been developed for spectral analysis of asymmetric top molecules. The high order centrifugal distortion terms are found to be non-negligible even for the low-lying rotational transitions of molecules, such as H2 18O, subjected to severe centrifugal distortion effect, and for the high-lying rotational transitions of molecules, such as 14N16O2 subjected to the moderate centrifugal distortion effect.

Religion has long been playing an important role in influencing human behavior, however, its marketing value as a predictor of consumer behavior has not been adequately examined even though studies in the marketing literature argue that religion influence both behavior and purchasing decisions. This paper examines the effect of religiosity on consumer choice and is based on the proposition that religiosity significantly influences shopping behavior. Using the purchase of a mobile phone as the basis, the research tests the shopping behavior of Christians in China. The results indicate that a kind of shopper, namely trend shopper is consistently related to religiosity, suggesting that religiosity should be considered as a possible determinant of shopping behavior in the future.

We have studied highly excited sodium in various electric fields, parallel electric and magnetic fields, with one sigma and pi photon irradiation, and even in a magnetic field with a complex laser polarization configuration. The sigma spectra shows a simple linear Stark effect with the applied electric field, while the pi spectra exhibits a strong non-linear dependence on the electric field. The pi transitions in parallel fields show a similar behavior to that in a pure electric field but the spectra get more smooth due to the magnetic field. The diamagnetic spectrum with laser polarization angles between 0 and pi/2 proves that it can be reproduced by simple linear combination of pi and sigma components, indicating there is no interference between the pi and sigma channels. A full quantum calculation considering the quantum defects accounts for all the observations. The quantum defects, especially for the channel n pi, play an important role in the spectral profile.

Through an analysis of the nearest neighbor level spacing statistics for atoms in parallel electric and magnetic fields, we investigate the evolution of the electron dynamics as electric field strength increases. In the 'inter-l mixing' predominant region, the electron shows complex dynamics while in the 'inter-n mixing' predominant region, its dynamics behaves in a relatively stable way and the characteristic quantity xi shows a slight oscillation. Comparing the dynamics for hydrogen and barium, we find that the core effect makes the main contribution to the chaotic behavior in non-hydrogen atoms.

We report on the experimental spectral observations of barium in parallel electric and magnetic fields. The laser pulse is linearly polarized along or perpendicular to the fields, leading to the states m = 0 and the states m = +/- 1 populated, respectively, by one photon excitation. By sweeping the electric field, we observe the linear and nonlinear splitting of the diamagnetic spectrum as the electric field increases. The spectral anticrossing is induced by the atomic core effect. The Stark spectrum also shows an obvious nonlinear quadratic behavior when the applied magnetic field varies strongly. All spectra are well explained by the full quantum calculation after taking the quantum defect effects of the channel ns up to nf into account.

We calculate the diamagnetic spectrum of lithium at highly excited states up to the positive energy range using the exact quantum defect theory approach. The concerned excitation is one-photon transition from the ground state 2s to the highly excited states np with pi and sigma polarizations respectively. Lithium has a small quantum defect value 0 : 05 for the np states, and its diamagnetic spectrum is very similar to that of hydrogen in the energy range approaching the ionization limit. However, a careful calculation shows that the spectrum has a significant discrepancy with that of hydrogen when the energy is lower than -70 cm(-1). The effect of the quantum defect is also discussed for the Stark spectrum. It is found that the sigma transition to the np states in an electric field has a similar behavior to that of hydrogen due to zero interaction with channel ns.

We present observations of Stark spectra of barium in highly excited Rydberg states in the energy region around n = 35. The one-photon excitation concerns the pi transition. The observed Stark spectra at electric fields ranging from 0 to 60 V.cm(-1) are well explained by the diagonalization of the Hamiltonian incorporating the core effects. From the Stark maps, the anti-crossings between energy levels are identified experimentally and theoretically. The time of flight spectra at the specified Stark states are recorded, where the deceleration and acceleration of barium atoms are observed. This is very consistent with the prediction derived from the Stark maps from the point of view of energy conservation.

A theoretical calculation is carried out to investigate the spectrum of a barium Rydberg atom in an external magnetic field. Using an effective approach incorporating quantum defect into the centrifugal term in the Hamiltonian, we reexamine the reported spectrum of the barium Rydberg atom in a magnetic field of 2.89 T [J. Phys. B 28 L537 (1995)]. Our calculation employs B-spline basis expansion and complex coordinate rotation techniques. For single photon absorption from the ground 6s2 to 6snp Rydberg states, the spectrum is not influenced by quantum defects of channels ns and nd. The calculation is in agreement with the experimental observations until the energy reaches E = −60 cm−1. Beyond this energy, closer to the threshold, the calculated and experimental results do not agree with each other. Possible reasons for their discrepancies are discussed. Our study affirms an energy range where the diamagnetic spectrum of the barium atom can be explained thoroughly using a hydrogen model potential.

We present photoelectron spectra (PES) of xenon subject to ultrashort intense laser pulses at 400 nm. The intensity-dependent PES exhibit the dominance of ac-Stark-shifted multiphoton resonances in a multiphoton ionization process. A distinct difference in the spectra with different laser polarization states (i.e., linearly and circularly polarized states) is revealed and can be understood in terms of the quantum selection rule, which restricts the angular momentum of states that may shift into multiphoton resonances. Furthermore, the intensity dependence of the resonance-enhanced electron yield is analyzed in the context of multiphoton Landau-Zener theory. The model calculation results considering the focal volume effect are in good agreement with the experimental observation.

We have studied the ionization of Rydberg hydrogen atom near a metal surface with a semiclassical analysis of photoionization microscopy. Interference patterns of the electron radial distribution are calculated at different scaled energies above the classical saddle point and at various atom—surface distances. We find that different types of trajectories contribute predominantly to different manifolds in a certain interference pattern. As the scaled energy increases, the structure of the interference pattern evolves smoothly and more types of trajectories emerge. As the atom approaches the metal surface closer, there are more types of trajectories contributing to the interference pattern as well. When the Rydberg atom comes very close to the metal surface or the scaled energy approaches the zero field ionization energy, the potential induced by the metal surface will make atomic system chaotic. The results also show that atoms near a metal surface exhibit similar properties like the atoms in the parallel electric and magnetic fields.

We present a simple and efficient method for measuring the atomic lifetimes in order of tens of microseconds and demonstrate it in the lifetime determination of barium Rydberg states. This method extracts the lifetime information from the time-of-flight spectrum directly, which is much more efficient than other methods such as the time-delayed field ionization and the traditional laser induced fluorescence. The lifetimes determined with our method for barium Rydberg 6snp (n = 37-59) series are well coincident with the values deduced from the absolute oscillator strengths of barium which were given in the literature [J. Phys. B 14 ( 1981) 4489, 29 (1996) 655] on experiments.

This paper investigates the photodetachment of the negative hydrogen ion H- near an elastic wall in a magnetic field. The magnetic field confines the perpendicular motion of the electron, which results in a real three-dimensional well for the detached electron. The analytical formulas for the cross section of the photodetachment in the three-dimensional quantum well are derived based on both the quantum approach and closed-orbit theory. The magnetic field and the elastic surface lead to two completely different modulations to the cross section of the photodetachment. The oscillation amplitude depends on the strength of the magnetic field, the ion-wall distance and the photon polarization as well. Specially, for the circularly polarized photon-induced photodetachment, the cross sections display a suppressed (E - E-th)(1/2) threshold law with energy E in the vicinity above Landau energy E-th, contrasting with the (E - Eth)(-1/2) threshold law in the presence of only the magnetic field. The semiclassical calculation fits the quantum result quite well, although there are still small deviations. The difference is attributed to the failure of semiclassical mechanics.