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Full-Text Articles in Physics
Semiclassical Theory Of Weighted Spectra For Regular Systems: Absorption Spectra And Decay Rates, M. W. Beims, V. Kondratovich, John B. Delos
Semiclassical Theory Of Weighted Spectra For Regular Systems: Absorption Spectra And Decay Rates, M. W. Beims, V. Kondratovich, John B. Delos
Arts & Sciences Articles
We derive a simple semiclassical representation to describe the large-scale structure of the spectrum of regular systems weighted by some arbitrary function W. Examples of weighted spectra are the width-weighted spectrum, which represents the decay rate of an unstable system, and the oscillator-strength-weighted spectrum, which represents the photoabsorption rate. Semiclassical representations of such spectra involve stationary-phase contributions, which are periodic or closed orbits, and end-point contributions, which are loops on an extremal torus. The theory provides the link between semiquantal formulas and the closed-orbit theory of atomic photoabsorption. It also allows calculation of an average decay rate without knowledge …
Classically Forbidden Recurrences In The Photoabsorption Spectrum Of Lithium, V. Kondratovich, John B. Delos, Neal Spellmeyer, Daniel Kleppner
Classically Forbidden Recurrences In The Photoabsorption Spectrum Of Lithium, V. Kondratovich, John B. Delos, Neal Spellmeyer, Daniel Kleppner
Arts & Sciences Articles
We present data on the photoabsorption spectrum of lithium atoms in an electric field at energies between the saddle point of the Stark potential and below the field-free ionization threshold. The spectrum displays a sequence of sharp resonances and a sequence of broad ones. We find that the broad resonances arise from the classically forbidden reflection of waves above a dynamical potential barrier. The recurrence spectrum is also observed and it is dramatically affected by above-barrier reflections. We have developed a semiclassical theory that interprets the spectra using quasiclassical trajectories that undergo above-barrier reflection.
Recurrence Spectroscopy In Time-Dependent Fields, M. R. Haggerty, John B. Delos
Recurrence Spectroscopy In Time-Dependent Fields, M. R. Haggerty, John B. Delos
Arts & Sciences Articles
Closed-orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. We derive an alternative version of closed-orbit theory that applies when the external fields are time dependent. We compare the results of this theory with experiments on lithium atoms in a weak oscillating electric field.
Broadening, Shifting, And Line Asymmetries In The 2←0 Band Of Co And Co–N2: Experimental Results And Theoretical Calculations, Adriana Predoi-Cross, J. P. Bouanich, D. Chris Benner, A. D. May, J. R. Drummond
Broadening, Shifting, And Line Asymmetries In The 2←0 Band Of Co And Co–N2: Experimental Results And Theoretical Calculations, Adriana Predoi-Cross, J. P. Bouanich, D. Chris Benner, A. D. May, J. R. Drummond
Arts & Sciences Articles
We have measured the room temperature, widths, pressure shifts, and line asymmetry coefficients for many transitions of the first overtone band of CO and CO perturbed by N2." role="presentation" style="display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px 2px 0px 0px; margin: 0px; position: relative;">N2.N2. The broadening coefficients were obtained with an accuracy of about 1%. The pure CO profiles have been fitted by a Voigt profile while the CO–N2" role="presentation" style="display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: …