B-spline Breit?Pauli R-matrix calculations for electron collisions with argon atoms

We have applied the Breit–Pauli B-spline R-matrix method described earlier (J. Phys. B: At. Mol. Opt. Phys. 37 (2004) 2173) to the treatment of e–Ar collisions. An individually optimized, term-dependent set of non-orthogonal valence orbitals is used to account for the strong term dependence in the one-electron orbitals. Concentrating on the near-threshold regime for excitation of the 3p54s manifold, we obtain excellent agreement with benchmark experimental data for the production of metastable atoms and for excitation of the VUV-emitting J = 1 levels. A detailed partial-wave resolved resonance analysis shows that many of the structures listed by Buckman and Clark (Rev. Mod. Phys. 66 (1994) 539) are composed of overlapping resonances. These, together with their principal components and decay channels, are identified and, in some cases, alternative classifications are suggested.

[1]  F. Smith,et al.  Lifetime Matrix in Collision Theory , 1960 .

[2]  M. Bentley.  Orthogonality constraints in finite basis set calculations , 1994 .

[3]  M. V. Malyshev,et al.  Ultrahigh frequency versus inductively coupled chlorine plasmas: Comparisons of Cl and Cl2 concentrations and electron temperatures measured by trace rare gases optical emission spectroscopy , 1998 .

[4]  V. Zeman,et al.  Electron-impact excitation of the and states of neon , 1997 .

[5]  J. E. Chilton,et al.  Electron-impact excitation cross sections of neon , 2000 .

[6]  J. Brunt,et al.  Resonance structure in elastic electron scattering from helium, neon and argon , 1977 .

[7]  C. Clark,et al.  Atomic negative-ion resonances , 1994 .

[8]  V. M. Burke,et al.  Farm — A flexible asymptotic R-matrix package , 1995 .

[9]  J. Brunt,et al.  The classification of resonances in electron impact on neon, argon, krypton and xenon , 1976 .

[10]  J. Brunt,et al.  Near-threshold electron impact excitation of ultraviolet-emitting levels of neon, argon, krypton and xenon atoms , 1977 .

[11]  A. Grum-Grzhimailo,et al.  Excitation of the 2p levels of inert gases by electrons in the distorted-wave approximation: neon and argon , 1990 .

[12]  C. M. Maloney,et al.  Integral and differential cross section for electron-impact excitation of 12 of the lowest states of argon , 1998 .

[13]  F. Martín,et al.  Applications of B-splines in atomic and molecular physics , 2001 .

[14]  K. Bartschat,et al.  Electron impact excitation of rare gases: differential cross sections and angular correlation parameters for neon, argon, krypton and xenon , 1987 .

[15]  P G Burke,et al.  Electron - atom scattering at low and intermediate energies using a pseudo-state/ R-matrix basis , 1996 .

[16]  C. Fischer,et al.  Photodetachment of He− 1s2s2p 4Po in the region of the 1s threshold , 2002 .

[17]  J. Tennyson,et al.  TIMEDEL: A program for the detection and parameterization of resonances using the time-delay matrix , 1998 .

[18]  I. Fabrikant,et al.  Electron impact formation of metastable atoms , 1988 .

[19]  H. V. D. Hart,et al.  B-spline methods in R-matrix theory for scattering in two-electron systems , 1997 .

[20]  Klaus Bartschat,et al.  The R-matrix with pseudo-states method: Theory and applications to electron scattering and photoionization , 1998 .

[21]  P. Hammond.  LETTER TO THE EDITOR: Benchmark energies of negative ion states of argon , 1996 .

[22]  K. Bartschat,et al.  Non-statistical branching ratios for excitation of (np2(n+1)s) 1.3P degrees 0,1,2 states in noble gases , 1992 .

[23]  Keith A. Berrington,et al.  Atomic and Molecular Processes: an R-Matrix Approach , 1993 .

[24]  Roy,et al.  Analysis of the first Feshbach resonances in electron collisions in rare gases. , 1993, Physical review. A, Atomic, molecular, and optical physics.

[25]  D. C. Griffin,et al.  Electron-impact excitation of neon: a pseudo-state convergence study , 2004 .

[26]  M. Seaton.  OSCILLATOR STRENGTHS IN NE I , 1998 .

[27]  R. McEachran,et al.  Elastic scattering of electrons from neon and argon , 1983 .

[28]  F. H. Read,et al.  High-resolution electron impact excitation functions of metastable states of neon, argon, krypton and xenon , 1983 .

[29]  J. Ajello,et al.  Electron-Impact-Induced Emission Cross Sections of Neon in the Extreme Ultraviolet , 1996 .

[30]  J. Bieroń,et al.  Hyperfine-structure calculations in Xe II , 2000 .

[31]  C. Fischer,et al.  Breit–Pauli and Dirac–Hartree–Fock energy levels and transition probabilities in neutral argon , 2004 .

[32]  Nigel R. Badnell,et al.  Photoionization - excitation of helium using an R-matrix with pseudostates method , 1997 .

[33]  Robert McEachran,et al.  Relativistic distorted-wave calculation of electron impact excitation of xenon , 1991 .

[34]  Saha Hp.  Erratum: Low-energy elastic scattering of electrons from neon atoms , 1989 .

[35]  L. E. Machado,et al.  Coherence parameters, spin-asymmetry and spin-polarization functions for electron impact excitation of neon , 1994 .

[36]  J. Brunt,et al.  A study of resonance structure in neon, argon, krypton and xenon using metastable excitation by electron impact with high energy resolution , 1976 .

[37]  K. Berrington,et al.  RMATRX1: Belfast atomic R-matrix codes , 1995 .

[38]  W. Graham,et al.  Role of low-energy electrons in Ar emission from low-pressure radio frequency discharge plasma , 1999 .

[39]  B. S. Gray,et al.  Gain measurements at 543 nm in helium neon laser discharges , 1996 .

[40]  Vincent Puech,et al.  Collision cross sections and transport parameters in neon and xenon , 1991 .

[41]  O. Zatsarinny,et al.  Low-energy electron collisions with atomic oxygen: R-matrix calculation with non-orthogonal orbitals , 2001 .

[42]  C. Fischer,et al.  The use of basis splines and non-orthogonal orbitals in R-matrix calculations: application to Li photoionization , 2000 .

[43]  P. Teubner,et al.  LETTER TO THE EDITOR: Excitation of the 3p? state of neon by high-resolution electron impact , 1998 .

[44]  P. Teubner,et al.  Differential cross sections and cross-section ratios for the electron-impact excitation of the neon 2p 5 3s configuration , 2002 .

[45]  C. Clark,et al.  Electron scattering by neon in resonance regions , 1985 .

[46]  D Drakova,et al.  Theoretical modelling of scanning tunnelling microscopy, scanning tunnelling spectroscopy and atomic force microscopy , 2001 .

[47]  Saha.  Low-energy elastic scattering of electrons from neon atoms. , 1989, Physical review. A, General physics.

[48]  J. Giuliani,et al.  Electron-impact excitation from the (4p 5 5s) metastable states of krypton , 2002 .

[49]  A. Hibbert.  CIV3 — A general program to calculate configuration interaction wave functions and electric-dipole oscillator strengths , 1984 .

[50]  L. E. Machado,et al.  Electron-impact excitation of some low-lying levels of neon , 1984 .

[51]  C. Clark,et al.  Regularities of Negative Ion Resonances , 1987, Topical Meeting on Multiple Excitations of Atoms.

[52]  C. Fischer,et al.  Oscillator strengths for transitions to high-lying excited states of carbon , 2002 .

[53]  K. Bartschat,et al.  Benchmark comparisons for near-threshold electron-impact excitation of Ar metastable levels , 2001 .

[54]  C. Fischer,et al.  A general program for computing angular integrals of the Breit-Pauli Hamiltonian with non-orthogonal orbitals , 2000 .

[55]  V. Zeman,et al.  Near-threshold electron-impact excitation of the vacuum-ultraviolet resonance transitions in Ne, Ar, Kr, and Xe , 1998 .

[56]  D. Kilbane,et al.  4f collapse, level density inflation and the emergence of 'compound-like' atomic states in rare earth ions , 2002 .

[57]  D. C. Cartwright,et al.  Electron-impact-excitation cross sections for electronic levels in neon for incident energies between 25 and 100 eV , 1984 .

[58]  V. Zeman,et al.  Electron-impact excitation from the(3p54s)metastable states of argon , 1999 .

[59]  J. Giuliani,et al.  Electron-impact excitation to the 4 p 5 5 s and 4 p 5 5 p levels of Kr I using different distorted-wave and close-coupling methods , 2001 .

[60]  K. Taylor,et al.  CORRIGENDUM: An investigation of the [(3p5)3/2,1/2(4s)2] resonances in the elastic scattering of electrons by argon atoms , 1982 .

[61]  F. H. Read,et al.  Highly-excited double Rydberg states of He- , 1983 .

[62]  P. Burke,et al.  Near-threshold electron impact excitation of argon atoms , 1982 .

[63]  Y. Itikawa,et al.  Excitation of xenon by electron impact , 1997 .