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Doppler broadening
About: Doppler broadening is a research topic. Over the lifetime, 5509 publications have been published within this topic receiving 92552 citations.
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TL;DR: In this article, a simple treatment of the Doppler effect comprising of not only line shift and broadening, but also of the effect on the angular distribution for line broadening is presented, and the potential or Berry effect for fast autionization processes is discussed.
Abstract: This is the first of a series of papers dealing with the spectroscopy of electrons from heavy-ion-atom collisions The paper presents a simple treatment of the Doppler effect comprising of not only line shift and broadening, but also of the effect on the angular distribution For line broadening, previous approximations are replaced by a more accurate, but still simple, expression The potential or Berry effect for fast autionization processes is discussed Owing to interaction with the Doppler effect, the Berry width vanishes under certain conditions The experimental conditions are outlined and illustrated by sample calculations
38 citations
TL;DR: In this paper, the authors determined the line shapes and intensities for coherent anti-Stokes Raman scattering (CARS) at saturation laser intensities by solving the time-dependent density-matrix equations numerically.
Abstract: Line shapes and intensities for coherent anti-Stokes Raman scattering (CARS) at saturation laser intensities are determined for nitrogen vibrational Q-branch lines by solving the time-dependent density-matrix equations numerically. We have previously performed measurements of saturated CARS line shapes in pure nitrogen by using nearly Fourier-transform-limited pump and Stokes lasers. The experimental laser pulse shapes, Stark effects, Doppler broadening, and the nonresonant background are incorporated in the numerical calculations. The numerical results show good agreement with the high-resolution measurements of saturated CARS line shapes. The lines show prominent saturation dips, and agreement between theory and experiment is excellent in terms of the depth and the width of the dips. The numerical results indicate that the Doppler effect tends to broaden and to deepen the dip in highly saturated lines, an effect that cannot be explained by a steady-state theory.
38 citations
TL;DR: In this paper, the X-ray emission spectrum of an ion having an inner-shell vacancy moving through a solid is discussed using Weisskopf's theory of collision broadening.
Abstract: For pt. I, see abstr. A13527 of 1974. The X-ray emission spectrum of an ion having an inner-shell vacancy moving through a solid is discussed using Weisskopf's theory of collision broadening (1933). In particular the approximations involved in a previous treatment which used the 'static' approximation are clarified. The analysis of the problem is illustrated by a direct evaluation of the emission spectrum of a model system by means of a numerical Fourier transform. The calculation demonstrates that the simpler static approximation is adequate except near the classical cut-off frequency where the dynamic variation of the molecular orbitals causes a broadening beyond this cut-off frequency. An estimate of this broadening is given.
38 citations
TL;DR: In a clinical study, 78 carotid bifurcations were examined by pulsed Doppler ultrasonography and X-ray arteriography and the degree of spectral broadening was obtained from the ratio of the maximum to mean frequency at peak systole.
Abstract: In a clinical study, 78 carotid bifurcations were examined by pulsed Doppler ultrasonography and X-ray arteriography. Maximum Doppler frequencies greater than or equal to 3 kHz diagnosed stenoses of greater than or equal to 25% diameter reduction with a sensitivity of 73% and specificity of 79%. A quantitative analysis of the degree of spectral broadening was obtained from the ratio of the maximum to mean frequency at peak systole and improved the sensitivity and specificity to 90% and 98% respectively. All vessels greater than 40% stenosis were correctly classified as stenosed and all less than 20% stenosis were classified as normal.
37 citations
TL;DR: It is shown that the self-pulsing emission can still be observed when the typical residual Doppler broadening of an atomic beam is taken into account.
Abstract: Lasing without inversion (LWI) in specific models of closed three-level systems is analyzed in terms of nonlinear dynamics. From a linear stability analysis of the trivial nonlasing solution of the homogeneously broadened systems with on-resonance driving and laser fields, we find that, near lasing threshold, resonant closed $\ensuremath{\Lambda}$ and $V$ schemes yield continuous-wave LWI while resonant cascade schemes can give rise to self-pulsing LWI. The origin of this different behavior is discussed. For parameters of a real cascade system in atomic ${}^{138}\mathrm{Ba}$ we check numerically that the self-pulsing solution is stable in a broad range of nonzero detunings. It is shown that the self-pulsing emission can still be observed when the typical residual Doppler broadening of an atomic beam is taken into account.
37 citations