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 Orthogonalization methods (1)
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Articles 1  7 of 7
FullText Articles in Physics
Formation Of Positronium In E+ + H Collisions, Jack C. Straton, Richard J. Drachman
Formation Of Positronium In E+ + H Collisions, Jack C. Straton, Richard J. Drachman
Physics Faculty Publications and Presentations
Cross sections for positronium formation by capture from the negative hydrogen ion are given. Orthogonalization corrections to the Coulomb (firstorder) Born approximation (CBA) differential and total cross sections are calculated using approximate H wave functions of both Löwdin [Phys. Rev. 90, 123 (1953)] and Chandrasekhar [Astrophys. J. 100, 176 (1944)]. The present calculation of the CBA cross sections using the post interaction for Löwdin’s wave function (LCBAPS) disagrees with the calculation of Choudhury, Mukherjee, and Sural (CMS) [Phys. Rev. A 33, 2358 (1986)], whereas our results using the prior interaction agree. Thus, where CMS found an order of magnitude ...
Frequency Shifts Of Molecules At Rough Metal Surfaces, M. H. Hider, P.T. Leung
Frequency Shifts Of Molecules At Rough Metal Surfaces, M. H. Hider, P.T. Leung
Physics Faculty Publications and Presentations
The frequency shifts for dipolar transitions of molecules at rough metallic surfaces are studied in a phenomenological model following the approach of the authors' previous work [Phys. Rev. B 36, 4664 (1987)], with the surface roughness modeled by a shallow grating profile in most cases. The main findings here are as follows: (1) such surfaceinduced shifts are indeed observable for molecular frequencies away from the surfaceplasmon resonance frequency of the metal; (2) the presence of surface roughness can either enhance or suppress the flatsurfaceinduced shifts, leading to extra morphologydependent resonances originated from the radiative coupling between the molecular emission and ...
FockTani Hamiltonian For Reactions Involving TwoElectron Atoms, Jack C. Straton
FockTani Hamiltonian For Reactions Involving TwoElectron Atoms, Jack C. Straton
Physics Faculty Publications and Presentations
The FockTani Hamiltonian is found for scattering processes involving up to two ions and two electrons. Possible boundstate species include one or two electrons bound on an ion fixed at the origin, and a oneelectron projectile atom. A diagrammatic technique is illustrated that simplifies the algebra of the transformation. Coulomb or planewave states are automatically generated by the same asymptotic Hamiltonian for all arrangement channels.
Double Excitation Of Helium By Fast Particles Of Charge Z, James H. Mcguire, Jack C. Straton
Double Excitation Of Helium By Fast Particles Of Charge Z, James H. Mcguire, Jack C. Straton
Physics Faculty Publications and Presentations
Results of calculations of double excitation of helium to n=2 states for fast projectiles of charge Z are presented. Nonzero Z^{3} contributions for single and double excitation occur only when timeordering contributions from the secondorder amplitude are nonzero. For double excitation, electron correlation must also be nonzero to obtain Z^{3} terms. The timeordering effects arise from virtual offenergyshell intermediate states. As with secondorder amplitudes for Thomas singularities in electron capture, the energynonconserving amplitude is connected to the secondorder energyconserving amplitude by a dispersion relation. Comparison is made with experiment.
FirstOrder Amplitude For General StateToState Transitions In Hydrogen By Projectile Impact, Jack C. Straton
FirstOrder Amplitude For General StateToState Transitions In Hydrogen By Projectile Impact, Jack C. Straton
Physics Faculty Publications and Presentations
The closed analytic form for boundstate transitions due to projectile impact is found in the intermediate representation. The coordinate integral is obtained by evaluating the remaining two integrals in the general multicenter integral derived previously [J.C. Straton, Phys. Rev. A 41, 71 (1990)]. Evaluating the remaining time integral depends upon relating a sum of modified Bessel functions of the second kind K_{N+1/2}(z) to a simple polynomial in 1/z. The results of Van Den Bos and De Heer [Physica 34, 333 (1967)] are shown to be missing a phase factor of (i)^{(l′+l)}
100 Kv Schottky Electron Gun, J. B. Mcginn, L. W. Swanson, N. A. Martin, M. A. Gesley, M. A. Mccord, R. Viswanathan, F. J. Hohn, A. D. Wilson, R. Nauman, Mark Utlaut
100 Kv Schottky Electron Gun, J. B. Mcginn, L. W. Swanson, N. A. Martin, M. A. Gesley, M. A. Mccord, R. Viswanathan, F. J. Hohn, A. D. Wilson, R. Nauman, Mark Utlaut
Physics Faculty Publications and Presentations
We present a comparison between experimental results and computer calculations on a high current, high resolution single lens electrostatic 100 kV Schottky electron gun. One promising application for such an electron gun is for direct electron‐beam patterning of x‐ray masks. The high energy helps provide precise patterning of the thick resist, maintains vertical resist profiles, and minimizes the proximity effect. The gun was designed to operate from 25 to 100 kV, capable of focus at a distance of 145–245 mm with a magnification of 1.15. The emitter, of apex radius ∼0.6 μm operated at 1800 ...
Microscopic Irreversibility And Gibbs Entropy, John D. Ramshaw
Microscopic Irreversibility And Gibbs Entropy, John D. Ramshaw
Physics Faculty Publications and Presentations
In a recent paper of the same title [J. NonEquilib. Thermodyn., 15 (1990), 151], Liboff observed that the finegrained Gibbs entropy of a canonical Hamiltonian system remains constant in time even for Hamiltonians that are not even in momenta and consequently violate timereversal invariance (TRI). Here we extend this observation to noncanonical Hamiltonian systems, including systems with singular Poisson tensors and pseudoHamiltonian systems that violate the Jacobi identity. Necessary and sufficient conditions are given for the Gibbs entropy to be constant in such systems. The concept of TRI is not in general meaningful for such systems, but it is shown ...