This is the first of two papers that develop theory oscillatory spectra. When an atom placed in a magnetic field, and absorption spectrum into states close to ionization threshold measured at finite resolution, so individual energy levels are not resolved, it found as function superposition sinusoidal oscillations. These present quantitative this phenomenon. In paper, we describe physical ideas underlying simplest possible way, our calculations based upon theory. second developed full...

Measurements of the absorption spectrum near ionization threshold for an atom in a strong magnetic field showed that is superposition many oscillatory terms (``quasi-Landau oscillations''). We have developed quantitative theory which shows each classical closed electron orbit begins and ends nucleus contributes term to average oscillator strength. The gives new understanding behavior under combined Coulomb Lorentz forces, it elucidates roles isolated orbits chaotic systems. first results...

Standard closed-orbit theory is applied to derive the photodetachment cross section of ${\mathrm{H}}^{\ensuremath{-}}$ in presence a static electric field. The result agrees with one derived earlier using quantum approach involving momentum-space wave function and stationary-phase approximation. advantage present derivation ability separate oscillation term smooth background identify two terms different physical origins.

view Abstract Citations (66) References (31) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Radiative Association of C and O + Dalgarno, A. ; Du, M. L. You, J. H. formation CO(+) CO in the expanding metal-rich ejecta SN 1987A has been discussed by Lepp et al. (1988) Petuchowski (1989), who concluded that it probably proceeded through radiative association C(+) to form reactions (1) - hnu, followed charge transfer with O, (2) O(+), CO, (3) hnu. estimated...

Simple analytic formulas are presented for the photodetachment cross section of ${\mathrm{H}}^{\mathrm{\ensuremath{-}}}$ in presence parallel electric and magnetic fields. A rich array spectra displayed that illustrate strong dependence on polarization photons

Total photodetachment cross section of H− near a reflecting wall was studied recently by Yang et al using closed-orbit theory (2006 J. Phys. B: At. Mol. Opt. 39 1855). The main effect shown to induce an oscillation in the section. In this paper, we study theoretical imaging method, which is very different from method theory. enables us derive total and differential sections straightforward way. We considered both soft case hard case, they differ values phase loss when detached-electron...

We have calculated the energy spectrum of a highly excited atom in parallel electric and magnetic fields. The eigenvalues were obtained by semiclassical quantization action variables from first-order classical perturbation theory. For field strengths studied, electron moves on Kepler ellipse whose orbital parameters evolve slowly time, theory reduces problem to just one degree freedom. Action action. analysis leads directly correlation diagram which connects eigenstates Stark effect those...

A negative ion irradiated by a laser provides coherent source of electrons propagating out from the location ion. The total escape rates when is placed inside an open cavity in shape wedge are studied. It shown that induces significant oscillations because quantum interference effects. In particular, it that, for with opening angle $\ensuremath{\pi}/N$, where $N$ arbitrary positive integer, there $(2N\ensuremath{-}1)$ induced rates. As demonstration, case $\ensuremath{\pi}/5$ calculated and...

A theoretical formulation is presented of the predissociation vibrational levels C 3Πg Rydberg state O2 in terms an inhomogeneous driven equation which takes account couplings between and lowest two valence states coupling states. The branching ratios for decay to end products O(3P)+O(1D) O(3P)+O(3P) are obtained it found that by a suitable choice potential energy curves interactions agreement can be with experimental data. Utility Landau–Zener model investigated shown highly successful...

We report a theoretical study of the escape rates Hénon-Heiles system above threshold. An analytic formula for rate as function energy is presented. also simulated escaping process by following motions large number particles. Two algorithms are employed to solve equations motion. One Runge-Kutta-Fehlberg method, and another recently proposed fourth order symplectic method. Our simulations show follows exponential laws. extracted from time dependence particle numbers in potential. The agree...

Using a high-frequency field superposed to linearly polarized bichromatic laser composed by wave with frequency $\ensuremath{\omega}$ and $2\ensuremath{\omega},$ we show it is possible enhance the intensity of group high harmonics in orders magnitude. These have frequencies about 30% higher than monochromatic-cutoff frequency, and, within three-step-model framework, correspond set electron trajectories for which tunneling ionization strongly suppressed. Particular features observed...

The spontaneous emission rate of an atom in dielectric slabs is shown to exhibit multiperiodic oscillations when the system scale varied. These are calculated using quantum electrodynamics and analyzed ideas from closed-orbit theory. extracted frequencies rates by Fourier transform agree well with actions short photon closed orbits. interpreted as interferences emitted propagating on orbits leaving returning emitting atom. This study provides a new understanding process for atoms presence...

Understanding the interplay of interaction and disorder in quantum transport poses long-standing scientific challenges for theory experiment. While highly controlled ultracold atomic platforms combining interactions with spatially disordered lattices have led to remarkable advances, extension such studies phenomena high-dimensional systems, as three-dimensional Anderson metal-insulator transition has been limited. Kicked gases provide an alternate experimental platform that captures model...

We study the detached-electron flux distributions from photodetachment of a negative ion near repulsive center. Using semiclassical approach, we calculate electron on spherical detectors with various radii. The classically allowed angular range interference patterns screen increases as energy is increased. In range, find that there are always two trajectories going to observation point screen, inducing quantum patterns. have also extended formulas into tunneling region. reflect distribution...

The general correspondence principle specifies a relationship between wave functions and families of trajectories. For bounded systems with regular trajectories, this leads to the quantization action. also for finite-resolution spectra: oscillation in average density states, or oscillator strength as function energy, are connected periodic closed orbits. This holds independently whether classical trajectories orderly chaotic.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML"...

Eigenvectors for an electron in atom parallel electric and magnetic fields are calculated, a semiclassical interpretation of their behavior is obtained. can this case be regarded as ``wave functions angular momentum space.'' The matrix equation defining the eigenvectors written difference equation, then converted to pseudodifferential equation; systematic procedure used construct approximation. It found that same classical Hamiltonian has been previously calculate eigenvalues provides...

The spontaneous emission rate of an atom in a dielectric system with single interface is calculated using quantum electrodynamics and analyzed ideas from closed-orbit theory. shown to exhibit damping oscillation as the atomic distance varied. frequency matches very well prediction This study provides different perspective on atoms presence environments.

Calculations are carried out of the rate coefficient for radiative association ground state nitrogen oxygen atoms to form nitric oxide as a function temperature T . The is given by α( ) = 2.8(300/ 0.5 × 10 −17 cm³ s −1 Detailed predictions presented emission spectra accompanying process. widths profiles vary significantly with temperature.

In the artificial-channel method, an N-channel Hamiltonian describing multichannel decay of a system is embedded in (N+1)-channel Hamiltonian. The resonance energies and partial widths original physical problem are related simply to parameters Lorentzian forms inelastic-scattering probabilities problem, method permitting straightforward study half-collision process with algorithms developed for full scattering processes. utility demonstrated numerically model Child Lefebvre [Mol. Phys. 34,...

Near-threshold photodetachment microscopy of mononegative ions is theoretically studied when a homogeneous transverse magnetic field $\mathrm{B}$ superimposed to the static electric $\mathrm{E}$. The electron flux distribution obtained using two different approaches: quantum source theory with energy-Green function evaluated by means stationary phase approximation and closed-orbit theory. Here we describe physical ideas while developing in detail. Both theoretical methods yield consistent...

A theoretical study is made of the absorption cross section by a finite width laser pulse for atoms or negative ions in external fields. modified closed-orbit formula derived. It shown that reduces contributions from short closed orbits and completely eliminates long whose transit times are much greater than width. The theory applied to photodetachment ${\mathrm{H}}^{\mathrm{\ensuremath{-}}}$ presence static electric field pulse.

A procedure which offers computational advantages over the customary formalism is presented for calculating shifts of energy levels discrete states embedded in a continuum. Numerical procedures are described and applied to vibrational level B 3Σ−u state 16O2 interacting with 5Πu