Author name code: vanregemorter ADS astronomy entries on 2022-09-14 author:"van Regemorter, H." ------------------------------------------------------------------------ Title: The ``on the energy shell'' simplification of the impulse approximation in Rydberg atom-neutral collisions Authors: Hoang-Binh, D.; van Regemorter, H. Bibcode: 1999AIPC..467..336H Altcode: 1999sls..conf..336H Three types of calculations are compared according to the approximations used for the (e+B) scattering amplitude fe(q-->q'): (i) Exact impulse approximation (without any further approximation); (ii) Impulse approximation+``on the energy shell'' approximation; (iii) Impulse approximation+``on the energy shell'' approximation+``scattering length'' approximation. Preliminary results have been obtained for Na(n,l)+Ar collisions, suggesting that the ``on the energy shell'' approximation breaks down for large momentum transfers Q. Title: On the Ion Broadening of the 12 MU M lines of Atomic Magnesium Authors: Hoang-Binh, D.; van Regemorter, H. Bibcode: 1994IAUS..154..353H Altcode: No abstract at ADS Title: Stark broadening theory of solar Rydberg lines in the far-infrared spectrum Authors: van Regemorter, H.; Hoang-Binh, D. Bibcode: 1993A&A...277..623V Altcode: Line broadening theory is revisited to obtain simple formulae, in the specific case of isolated lines, resulting from transitions between nearly degenerate states of atomic magnesium. Both the widths and shifts, due to collisions with electrons and positive ions, are obtained without any elaborate calculations for all the Rydberg lines (n‧, l‧) → (n,l‧+1), (5≤n‧≤ 1O n‧≤n<11, l>3), listed by Jefferies (1991). Validity conditions of the formulae are given for all the transitions under study.

It is shown that inelastic weak collisions usually dominate the widths, and that adiabatic ion collisions always dominate the shifts and thus determine their signs. The shifts appear as good diagnostics; e.g. for the peculiar case of the 6h-7i line near 12 μm, good agreement with observations is obtained for electron and ion densities close to those in the line forming region. Title: Electron-Ion Processes in Hot Plasmas Authors: Dubau, J.; van Regemorter, H. Bibcode: 1983aia..conf..221D Altcode: The authors discuss atomic processes in plasmas such as coronal and Tokamak plasmas with temperatures above 106K and electron densities Ne very low 1015 cm-3. Ion-electron processes are the most important mechanisms for populating the emitting levels. Emphasis is put on the use of a distorted-wave approximation which gives a reliable representation of the electron-ion system. The validity of approximate methods derived from perturbation theory for highly charged ions is also discussed. Title: Atoms in Astrophysical Plasmas Authors: van Regemorter, H. Bibcode: 1982ASIB...71..233V Altcode: 1982amct.conf..233V No abstract at ADS Title: The calculation of oscillator strengths and multipole radial integrals in the Coulomb approximation. Authors: Binh, D. H.; Prudhomme, M.; van Regemorter, H. Bibcode: 1979ApJ...230L.127B Altcode: A very simple method is presented which yields accurate values of multipole radial integrals in the Coulomb approximation, even for transitions involving high Rydberg states. It is noted that the smallest of the effective quantum numbers can be as large as 200. The previously described approach is briefly outlined with a slightly more general formulation applicable to any multipole transition in any ion with a specified net charge. A recurrence relation is pointed out which makes the calculation of the Gordon (1929) formula quite rapid and easy. Title: Molecular formation and destruction in the interstellar medium. Authors: van Regemorter, H.; Giusti Suzor, A.; Roueff, E. Bibcode: 1979atph.conf.....V Altcode: No abstract at ADS Title: A new calculation of the radiative association rate of the CH+ radical: comparison between semiclassical and quantal results (interstellar abundance) Authors: Giusti-Suzor, A.; Roueff, E.; van Regemorter, H. Bibcode: 1976JPhB....9.1021G Altcode: No abstract at ADS Title: On simple quantum theories of pressure broadening: the exact resonance approximation applied to Lyman alpha. Authors: Tran Minh, N.; Feautrier, N.; van Regemorter, H. Bibcode: 1976JQSRT..16..849T Altcode: No abstract at ADS Title: Negative ion formation by radiative electron attachment on atoms. Authors: Janev, R. K.; van Regemorter, H. Bibcode: 1974A&A....37....1J Altcode: The problem of radiative electron attachment on atoms at thermal energies is considered. Analytical expressions both for reaction cross section and rate coefficient are obtained in closed form. The distortion of the electronic motion in the initial state due to the scattering effects by the long range part of the atomic potential is explicitly taken into account. The low temperature dependence of the reaction rate coefficient for electron capture into an s- or p-final state is discussed and explicit expressions of these coefficients are given for several cases of special astrophysical and aeronomical interest. Title: Fundamental spectroscopic data (Données spectroscopiques fondamentales). Authors: Cook, A. H.; Edlén, B.; Kessler, K. G.; Garstang, R. H.; van Regemorter, H.; Moore-Sitterly, C.; Phillips, J. G. Bibcode: 1973IAUTA..15..155C Altcode: No abstract at ADS Title: Spectral Line Broadening Authors: van Regemorter, H. Bibcode: 1972ama..conf...85V Altcode: No abstract at ADS Title: The Broadening by Neutral Hydrogen in the Solar Atmosphere Authors: Roueff, E.; van Regemorter, H. Bibcode: 1971A&A....12..317R Altcode: The broadening cannot be given by the van der Waals interaction, increasing the C. constant arbitrarily, as it is assumed in a recent paper by Holweger (1971). Key words: atomic physics - spectral line broadening - interatomic potential Title: Collisional Broadening of Spectral Lines Applications in Astrophysics and Plasma Physics Authors: van Regemorter, H. Bibcode: 1971peac.conf..897V Altcode: No abstract at ADS Title: Pressure Broadening of UV Lines Authors: van Regemorter, H. Bibcode: 1971HiA.....2..561V Altcode: No abstract at ADS Title: Pressure broadening of UV lines. Authors: van Regemorter, H. Bibcode: 1971adiu.conf..561V Altcode: No abstract at ADS Title: Excitation and Ionization by Electron Impact Authors: Bely, Oleg; van Regemorter, Henri Bibcode: 1970ARA&A...8..329B Altcode: No abstract at ADS Title: Spectral Line Broadening due to Atomic Collisions Authors: Roueff, E.; van Regemorter, H. Bibcode: 1969A&A.....1...69R Altcode: The width of spectral lines due to collisions with hydrogen atoms does not rise from the Van der Waals dispersion forces but from a shorter interaction. Title: Sur les raies de l'hydrogène. II. Importance respective des domaines << impact >> et quasistatique pour les électrons Authors: Feautrier, N.; Praderie, F.; van Regemorter, H. Bibcode: 1967AnAp...30...45F Altcode: No abstract at ADS Title: Spectral Line Broadening Authors: van Regemorter, Henri Bibcode: 1965ARA&A...3...71V Altcode: No abstract at ADS Title: L'éllargissement des raies spectrales par chocs Authors: Bréchot, S.; van Regemorter, H. Bibcode: 1964AnAp...27..432B Altcode: No abstract at ADS Title: L'élargissement des raies spectrales par chocs. II. - Théorie gélnélrale de l'éllargissement par chocs éllectroniques Authors: Bréchot, Sylvie; van Regemorter, Henri Bibcode: 1964AnAp...27..739B Altcode: No abstract at ADS Title: Rate of Collisional Excitation in Stellar Atmospheres. Authors: van Regemorter, Henri Bibcode: 1962ApJ...136..906V Altcode: An approximate formula is proposed to compute the cross-section for excitation by electron impact for the optically allowed transitions in neutral atoms and in positive ions. Comparison is given with the semiclassical formula of Woolley and Allen. Tables are given of the rate of collisional de-excitation in the main-sequence stars. Title: Méthodes de calcul des sections d'excitation par chocs électroniques Authors: van Regemorter, H. Bibcode: 1960AnAp...23..817V Altcode: No abstract at ADS Title: Electron impact excitation of positive ions: application to Ca+ 4s - 4p and 3d-4p Authors: van Regemorter, H. Bibcode: 1960MNRAS.121..213V Altcode: A review is given of different approximate methods for computing cross sections for transitions in positive ions produced by electron impact. It is shown that it Is necessary to take into account the distortion by the ion field, and, for strong optically allowed transitions, one must allow for strong coupling effects. Application to the 4p and 4p - 3d transitions in singly ionized calcium shows that the neglect of strong coupling effects overestimates the cross sections. However, our results, computed with a Coulomb distorted wave approximation, with allowance for strong coupling effects, are much bigger than those of Jefferies, the reason being that he considered only one value (1 = i) of the angular momentum of the incident electron, whereas the main contribution is shown to occur for 1=4. The Bethe approximation, with allowance for Coulomb distortion, implies in fact two different approximations: the weak coupling approximation and the "long range approximation ". It is possible to make corrections for strong coupling effects and, for strong allowed transitions such as 4s - 4p and 4p - 3d in Ca+, this method gives good results in a very simple way. Title: Recherches sur les problèmes théoriques de classification: II. Le calcul des raies d'absorption dans les spectres stellaires Authors: van Regemorter, H. Bibcode: 1959AnAp...22..341V Altcode: No abstract at ADS Title: Recherches sur les problèmes théoriques de classification: I. Les courbes de croissance dans la théories du transfert radiatif Authors: van Regemorter, H. Bibcode: 1959AnAp...22..249V Altcode: No abstract at ADS Title: Recherches sur les problèmes théoriques de classification stellaire IV. Applications aux problèmes de classification Authors: van Regemorter, H. Bibcode: 1959AnAp...22..681V Altcode: No abstract at ADS Title: Recherches sur les problèmes théoriques de classification: III. L'élargissement des raies de l'hydrogène Authors: van Regemorter, H. Bibcode: 1959AnAp...22..363V Altcode: No abstract at ADS Title: La mesure de la largeur équivalente d'une raie spectrale. L'influence du pouvoir de résolution Authors: Pecker, Jean-Claude; van Regemorter, Henri Bibcode: 1952AnAp...15..363P Altcode: No abstract at ADS