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Full-Text Articles in Physical Sciences and Mathematics
Quantum Manifestations Of Bifurcations Of Classical Orbits: An Exactly Solvable Mode, Aaron D. Peters, Charles Jaffé, John B. Delos
Quantum Manifestations Of Bifurcations Of Classical Orbits: An Exactly Solvable Mode, Aaron D. Peters, Charles Jaffé, John B. Delos
Arts & Sciences Articles
We examine photodetachment of H− in parallel electric and magnetic fields, hν+H−→H+e− using semiclassical approximations. The fields cause the electron to return to the atom, producing recurrences that are visible as interference oscillations in the photodetachment cross section. As the energy is varied, new returning orbits are created through bifurcations. Each such new recurrence increases the complexity of the absorption spectrum, and each bifurcation causes a local failure of the semiclassical approximation. The failure is repaired by a Fresnel diffraction integral.
Resonances And Recurrences In The Absorption Spectrum Of An Atom In An Electric Field, J. Gao, John B. Delos
Resonances And Recurrences In The Absorption Spectrum Of An Atom In An Electric Field, J. Gao, John B. Delos
Arts & Sciences Articles
We use closed-orbit theory to study the absorption spectrum of an atom in an electric field. In previous work we examined absorption spectra above the zero-field ionization threshold. Only one closed orbit exists there, and it is unstable. Now we examine the situation below threshold. Here, the orbit parallel to the electric field is stable and, as the energy decreases, many other closed orbits bifurcate out of it. These closed orbits have simple patterns, and the associated recurrences are most clear if the absorption spectrum is measured using a scaled-variables method. The relation between the semiclassical Einstein-Brillouin-Keller-Marcus (EBKM) theory and …
Recurrence Spectroscopy: Observation And Interpretation Of Large-Scale Structure In The Absorption Spectra Of Atoms In Magnetic Fields, J. Main, G. Wiebusch, K. Welge, J. Shaw, John B. Delos
Recurrence Spectroscopy: Observation And Interpretation Of Large-Scale Structure In The Absorption Spectra Of Atoms In Magnetic Fields, J. Main, G. Wiebusch, K. Welge, J. Shaw, John B. Delos
Arts & Sciences Articles
Measurements were made of the absorption spectrum of hydrogen atoms to levels near the ionization threshold in a strong magnetic field. Taking advantage of a classical scaling law, we varied the photon energy and the magnetic-field strength simultaneously, and measured absorption versus B−1/3 at fixed scaled energy, ɛ=E/(B/Bo)2/3. The absorption rate has sinusoidal fluctuations which are correlated with closed classical orbits of the electron. Fourier transformation of this signal gives peaks, which we interpret as ‘‘recurrence strength,’’ as a function of the classical action of the closed orbit. Closed-orbit theory gives formulas for these recurrence strengths. …