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- Atom-atom collisions (2)
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Articles 1 - 4 of 4
Full-Text Articles in Physics
A Criterion For Vortex Breakdown, R. E. Spall, T. B. Gatski, C. E. Grosch
A Criterion For Vortex Breakdown, R. E. Spall, T. B. Gatski, C. E. Grosch
CCPO Publications
A criterion for the onset of vortex breakdown over a wide range of the Reynolds number is proposed. Based upon previous experimental, theoretical, and numerical studies, as well as a new numerical study, an appropriately defined local Rossby number is used to delineate the region where breakdown occurs. Comparisons are made with previously suggested criticality parameters and the unique features of the proposed Rossby number parameter are shown. A number of previous theoretical studies concentrating on inviscid standing‐wave analyses for trailing wing‐tip vortices are reviewed and reinterpreted, along with the previous numerical and experimental studies, in terms of the Rossby …
Experimental Fine-Structure Branching Ratios For Na-Rare-Gas Optical Collisions, Mark D. Havey, F. T. Delahanty, Linda L. Vahala, Gary E. Copeland
Experimental Fine-Structure Branching Ratios For Na-Rare-Gas Optical Collisions, Mark D. Havey, F. T. Delahanty, Linda L. Vahala, Gary E. Copeland
Electrical & Computer Engineering Faculty Publications
Experimental ratios for branching into the fine-structure levels of the Na 3p multiplet, as a consequence of an optical collision with He, Ne, Ar, Kr, or Xe, are reported. The process studied is Na(3s2S1/2)+R+nhNNa(3p2Pj)+R+(n-1)hN, where R represents a rare-gas atom and where the laser frequency N is tuned in the wings of the Na resonance transitions. The branching ratios are defined as I(D1)/I(D2) where I(D1) and I(D2) are measured intensities of the atomic Na D1 and D2 lines. The ratios are determined for detunings ranging from about 650 …
On The Existence Of Periodic And Eventually Periodic Solutions Of A Fluid Dynamic Forced Harmonic Oscillator, Charlie H. Cooke
On The Existence Of Periodic And Eventually Periodic Solutions Of A Fluid Dynamic Forced Harmonic Oscillator, Charlie H. Cooke
Mathematics & Statistics Faculty Publications
For certain flow regimes, the nonlinear differential equation Y¨=F(Y)−G, Y≥0, G>0 and constant, models qualitatively the behaviour of a forced, fluid dynamic, harmonic oscillator which has been a popular department store attraction. The device consists of a ball oscillating suspended in the vertical jet from a household fan. From the postulated form of the model, we determine sets of attraction and exploit symmetry properties of the system to show that all solutions are either initially periodic, with the ball never striking the fan, or else eventually approach a periodic limit cycle, after a sufficient number of bounces away from …
Nonadiabatic Theory Of Fine-Structure Branching Cross Sections For Na-He, Na-Ne, And Na-Ar Optical Collisions, Linda L. Vahala, P. S. Julienne, Mark D. Havey
Nonadiabatic Theory Of Fine-Structure Branching Cross Sections For Na-He, Na-Ne, And Na-Ar Optical Collisions, Linda L. Vahala, P. S. Julienne, Mark D. Havey
Electrical & Computer Engineering Faculty Publications
The nonadiabatic close-coupled theory of atomic collisions in a radiation field is generalized to include electron spin and is used to consider the weak-field Na–rare-gas (RG) optical collision Na(2S1/2)+RG+nhν μNa(2Pj)+RG+(n-1)hν. The effects of detuning and incident energy on the branching into the atomic Na 3p2P3/2 and 3p2P1/2 states are examined. The cross sections σ(j) are found to have a strong asymmetry between red and blue detuning as well as a complex threshold and resonance structure dependence on energy. A partial cross-section analysis …