Relativistic transition wavelenghts and probabilities for spectral lines of Ne II

Transition wavelengths and probabilities for several 2p4 3p - 2p4 3s and 2p4 3d - 2p4 3p lines in fuorine-like neon ion (NeII) have been calculated within the multiconfiguration Dirac-Fock (MCDF) method with quantum electrodynamics (QED) corrections. The results are compared with all existing experimental and theoretical data

Resonance structures in the multichannel quantum defect theory for the photofragmentation processes involving one closed and many open channels

The transformation introduced by Giusti-Suzor and Fano and extended by Lecomte and Ueda for the study of resonance structures in the multichannel quantum defect theory (MQDT) is used to reformulate MQDT into the forms having one-to-one correspondence with those in Fano's configuration mixing (CM) theory of resonance for the photofragmentation processes involving one closed and many open channels. The reformulation thus allows MQDT to have the full power of the CM theory, still keeping its own strengths such as the fundamental description of resonance phenomena without an assumption of the presence of a discrete state as in CM.Comment: 7 page

Ab initio optical properties of Si(100)

We compute the linear optical properties of different reconstructions of the clean and hydrogenated Si(100) surface within DFT-LDA, using norm-conserving pseudopotentials. The equilibrium atomic geometries of the surfaces, determined from self-consistent total energy calculations within the Car-Parrinello scheme, strongly influence Reflectance Anisotropy Spectra (RAS), showing differences between the p(2x2) and c(4x2)reconstructions. The Differential Reflectivity spectrum for the c(4x2) reconstruction shows a positive peak at energies < 1 eV, in agreement with experimental results.Comment: fig. 2 correcte

Dynamics of collision processes

Investigations have been carried out of two- and three-photon detachment of the negative hydrogen ion (H[sup [minus]]) including effects of electron correlations, of two-color detachment of H[sup [minus]] with excitation of H(n=2), and of the [sup 3]P[sup e] state of H[sup [minus]]. Striking effects of long-range dipole field interactions have been demonstrated. Electron correlation effects on detachment cross sections have been quantified. Variational R-matrix calculations of photodetachment of Li[sup [minus]] have provided state-of-the-art agreement with recent experimental results. Electric Field effects on photodetachment of H[sup [minus]] above the H(n=2) threshold have also been elucidated

Photoionization of atoms. Final report, April 1, 1976-March 30, 1981

There were two main goals in the experimental study of photoionization. One was to provide accurate data on the results of photon-atom collisions, studying the absolute probability for ejecting electrons from specific orbitals and determining their angular distributions. Also of interest was the probability for one photon to eject two or more electrons. Another goal was to make measurements of specific interactions that would provide sensitive tests for the various theoretical approximations used in calculating photoionization cross sections. To achieve these two goals, care was taken in the selection of the various experiments and in the use of the most appropriate and sophisticated equipment. For example, the techniques of Photoelectron Spectroscopy, Photoionization - Mass Spectrometry, and Synchrotron radiation were used in many of the experiments

Triply differential (e,2e) cross sections for He from threshold to 50 eV above

Distorted wave calculations of the triply differential cross sections for electron-impact ionization of He are presented for electrons sharing [MATH] 50 eV excess energy (Ex) and having the coplanar, [MATH] geometry. The results are in good agreement with absolute experimental measurements of T. Rösel et al. [Phys. Rev. A 46 (1992) 2539-2552] and of A. J. Murray, M. B. Woolf, and F. H. Read [J. Phys. B 25 (1992) 3021-3036]. For final state electrons sharing 2 eV excess energy equally, many-body perturbation theory corrections to the authors' first order (e,2e) triply differential cross sections [Phys. Rev. A 45 (1992) 4588-4603] are also presented. These results indicate that singlet-triplet interchannel coupling effects in the final state are very significant ; that initial state correlations are significant near the perpendicular plane, i.e., [MATH] ; and that the polarization effects we include are insignificant. Finally, comparison of our first order results with the semiclassical quanta1 theory results of D. S. F. Crothers [J. Phys. B 19 (1986) 463-483] shows excellent agreement for excess energies [MATH] and for [MATH] ; for [MATH], the two results diverge as [MATH], indicating that experimental tests of the Wannier-Peterkop-Rau theory of three-body Coulomb breakup should be carried out in this energy region

Nondipole effects in double photoionization of He at 450 eV excess energy

Convergent close-coupling results for the triply differential cross section for double photoionization of He that include dipole-quadrupole terms are shown to have improved agreement (as compared to dipole approximation results) with recent experiments using linearly polarized light (Knapp A et al 2005 J. Phys. B: At. Mol. Opt. Phys. 38 615) for a number of kinematical configurations