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Full-Text Articles in Physics
Static-Electric-Field-Induced, High-Energy Plateau For Scattered X-Ray Photons In Laser-Assisted, X-Ray–Atom Scattering, Dejan B. Miloševic, Anthony F. Starace
Static-Electric-Field-Induced, High-Energy Plateau For Scattered X-Ray Photons In Laser-Assisted, X-Ray–Atom Scattering, Dejan B. Miloševic, Anthony F. Starace
Anthony F. Starace Publications
We consider scattering of x rays by H atoms in the presence of both a linearly polarized laser field and a static electric field. Results for the differential cross section as a function of the number of photons n exchanged with the laser field are presented. For x-ray–atom scattering in the presence of a 1014 W/cm2 laser field the differential cross section has a plateau only for emitted photons (n<0). Adding a static electric field gives rise to an extended plateau for absorbed photons (n>0), indicating a substantial increase of the scattered x-ray energies. We present a quasiclassical explanation of these results.
Analysis Of Doubly Excited State Resonances Below The Li(5p) Threshold In Li- Photodetachment, Chien-Nan Liu, Anthony F. Starace
Analysis Of Doubly Excited State Resonances Below The Li(5p) Threshold In Li- Photodetachment, Chien-Nan Liu, Anthony F. Starace
Anthony F. Starace Publications
Larger scale eigenchannel R-matrix calculations than those of Pan et al. [Phys. Rev. A53, 840 (1996)] confirm the prediction of a 2-meV-wide resonance feature at a photon energy of 5.421 eV in the Li (3s) partial cross section resulting from photodetachment of Li-. This resonance was neither clearly observed nor identified in measurements of Ljungblad et al. [Phys. Rev. Lett. 77, 3751 (1996)]. We identify this resonance as a N{υ}nA=5{1}6- state [having angular symmetry (K,T)A=(2,0) - or (n …
Target Dependence Of The Triply Differential Cross Section For Low Energy (E, 2e) Processes, Cheng Pan, Anthony F. Starace
Target Dependence Of The Triply Differential Cross Section For Low Energy (E, 2e) Processes, Cheng Pan, Anthony F. Starace
Anthony F. Starace Publications
The main purpose of this chapter is to review our calculations, whose aim is to explain the target dependence of the triply differential cross sections that has been observed in a number of recent experiments performed at relatively low energies above the ionization threshold for the two outgoing electrons leaving in opposite directions (θ12 = π). One reason for focusing on this θ12 = π geometry is that it is the most important geometry for near-threshold double-escape processes in the WPR theory. Another reason is that up to now, except for H and He targets, the triply differential …
Elementary Excitation Spectrum Of A Trapped Weakly Interacting Bose-Einstein Condensate, Mircea Marinescu, Anthony F. Starace
Elementary Excitation Spectrum Of A Trapped Weakly Interacting Bose-Einstein Condensate, Mircea Marinescu, Anthony F. Starace
Anthony F. Starace Publications
An analytic expression is presented for the elementary excitation spectrum of the Bose-Einstein condensate of a trapped boson system in the weakly interacting, low-density limit. Explicit analytic formulas for the elementary excitation spectrum are obtained for harmonic-oscillator traps. These formulas provide information about the behavior of the elementary excitation levels as a function of the number of atoms and their interaction strength for a given trap geometry. They also provide a low-density benchmark for results of fully numerical calculations.
Final-State-Interaction Effects On One- And Two-Photon Detachment Of H- In The Presence Of A Static Electric Field, Min-Qi Bao, Ilya I. Fabrikant, Anthony F. Starace
Final-State-Interaction Effects On One- And Two-Photon Detachment Of H- In The Presence Of A Static Electric Field, Min-Qi Bao, Ilya I. Fabrikant, Anthony F. Starace
Anthony F. Starace Publications
We present a detailed theoretical formulation of the problem of an electron moving in a static electric field, a laser field, and an atomic potential. Our formulation treats the electron-atom interaction in the zero-range potential approximation and employs both the quasienergy approach and an analytic expression for the Green’s function describing electron propagation in a combination of static and laser electric fields. Our formulation is applied to one- and two-photon detachment of H- in a strong static electric field and takes into account all final-state interactions of the detached electron with the static and laser fields and with the …
Absolute Triply Differential (E, 2e) Cross Sections For He In The Intermediate Energy Region With Comparison To Theory, J. Röder, H. Ehrhardt, Cheng Pan, Anthony F. Starace, Igor Bray, Dmitry V. Fursa
Absolute Triply Differential (E, 2e) Cross Sections For He In The Intermediate Energy Region With Comparison To Theory, J. Röder, H. Ehrhardt, Cheng Pan, Anthony F. Starace, Igor Bray, Dmitry V. Fursa
Anthony F. Starace Publications
Absolute triply differential (e, 2e) cross section measurements are presented for He at incident energies E0 = 32.6, 44.6, 64.6, and 104.6 eV with equal energy sharing and the θ12 = π configuration. Results of distorted partial-wave calculations agree with the measurements; those of convergent close-coupling calculations agree with the relative angular distributions, and with absolute values after rescaling by consideration of the singly differential cross section.
Invariant Representations Of Finite Rotation Matrices And Some Applications, N. L. Manakov, A. V. Meremianin, Anthony F. Starace
Invariant Representations Of Finite Rotation Matrices And Some Applications, N. L. Manakov, A. V. Meremianin, Anthony F. Starace
Anthony F. Starace Publications
Standard representations of finite rotation matrices (FRM) are defined by expressions that are wedded to two particular coordinate frames such as, e.g., are involved in the definition of Euler angles. We present here representations for the FRM in invariant tensor forms comprised of vectors defined in a space-fixed coordinate frame K. Three explicit expressions for a FRM are presented: First, in terms of tensor products of the spherical or Cartesian basis vectors of frame K, second in a differential form containing the tensor products of gradient operators, and, third, as the superposition of so-called “minimal” bipolar harmonics depending …
Novel Doubly Excited States Produced In Negative Ion Photodetachment, Anthony F. Starace
Novel Doubly Excited States Produced In Negative Ion Photodetachment, Anthony F. Starace
Anthony F. Starace Publications
Eigenchannel R-matrix calculations for photodetachment partial cross sections of H–, Li–, Na–, and Aℓ– provide results that are dominated by high doubly-excited states and that are in excellent agreement with available measurements. Propensity rules for doubly-excited states developed for H– apply also for heavier targets. However, states not observed in H– may be observed in the heavier target spectra owing to the non-Coulomb core. Finally the signature of particular doubly excited states changes drastically from one partial cross section to another.