Relativistic Distorted-wave Collision Strengths Research Articles

Relativistic distorted-wave collision strengths for [formula omitted] transitions in the 67 Li-like, F-like and Na-like ions with [formula omitted

Relativistic distorted-wave collision strengths have been calculated for all possible Δn=0 transitions, where n denotes the valence shell of the ground level, in the 67 Li-like, F-like and Na-like ions with Z in the range 26≤Z≤92. This choice produces 3 transitions with n=2 in the Li-like and F-like ions, and 10 transitions with n=3 in the Na-like ions. For the Li-like and F-like ions, the calculations were made for the six final, or scattered, electron energies E′=0.008,0.04,0.10,0.21,0.41, and 0.75, where E′ is in units of Zeff2 Ry with Zeff=Z−1.66 for Li-like ions and Zeff=Z−6.667 for F-like ions. For the Na-like ions, the calculations were made for the six final electron energies E′=0.0025,0.015,0.04,0.10,0.21, and 0.40, with Zeff=Z−8.34. In the present calculations, an improved “top-up” method, which employs relativistic plane waves, was used to obtain the high partial-wave contribution for each transition, in contrast to the partial-relativistic Coulomb–Bethe approximation used in previous works by Zhang, Sampson and Fontes [H.L. Zhang, D.H. Sampson, C.J. Fontes, At. Data Nucl. Data Tables 44 (1990) 31; H.L. Zhang, D.H. Sampson, C.J. Fontes, At. Data Nucl. Data Tables 48 (1991) 25; D.H. Sampson, H.L. Zhang, C.J. Fontes, At. Data Nucl. Data Tables 44 (1990) 209]. In those previous works, collision strengths were also provided for Li-, F- and Na-like ions, but for a more comprehensive set of transitions. The collision strengths covered in the present work should be more accurate than the corresponding data given in those previous works and are presented here to replace those earlier results.

Relativistic distorted-wave collision strengths for the 16 [formula omitted] optically allowed transitions with [formula omitted] in the 67 O-like ions with [formula omitted

Relativistic distorted-wave collision strengths have been calculated for the 16 Δn=0 optically allowed transitions with n=2 in the 67 O-like ions with nuclear charge number Z in the range 26≤Z≤92. The calculations were made for the four final, or scattered, electron energies E′=0.20,0.42,0.80, and 1.40, where E′ is in units of Zeff2 Ry with Zeff=Z−5.83. In the present calculations, an improved “top-up” method, which employs relativistic plane waves, was used to obtain the high partial-wave contribution for each transition, in contrast to the partial-relativistic Coulomb–Bethe approximation used in previous work by Zhang and Sampson [H.L. Zhang, D.H. Sampson, At. Data Nucl. Data Tables 82 (2002) 357]. In that earlier work, collision strengths were also provided for O-like ions, but for a more comprehensive data set consisting of all possible 45 Δn=0 transitions, six scattered energies, and the 79 ions with Z in the range 14≤Z≤92. The collision strengths covered in the present work should be more accurate than the corresponding data given by Zhang and Sampson [H.L. Zhang, D.H. Sampson, At. Data Nucl. Data Tables 82 (2002) 357] and are presented here to replace those earlier results.

Relativistic distorted-wave collision strengths and oscillator strengths for the [formula omitted] transitions with [formula omitted] in the 67 C-like ions with [formula omitted

Relativistic distorted-wave collision strengths have been calculated for the 185 Δn=0 transitions with n=2 in the 67 C-like ions with nuclear charge number Z in the range 26≤Z≤92. The calculations were made for the six final, or scattered, electron energies E′=0.03,0.08,0.20,0.42,0.80, and 1.40, where E′ is in units of Zeff2 Ry with Zeff=Z−4.17. In addition, electric dipole oscillator strengths are provided. In the present collision-strength calculations, an improved “top-up” method, which employs relativistic plane waves, was used to obtain the high partial-wave contribution for each transition, in contrast to the partial-relativistic Coulomb–Bethe approximation used in previous work by Zhang and Sampson [H.L. Zhang, D.H. Sampson, At. Data Nucl. Data Tables 63 (1996) 275]. In that earlier work, collision strengths were also provided for the same 185 Δn=0 transitions in C-like ions, but for the more limited list of 46 ions with Z in the range 9≤Z≤54. The collision strengths covered in the present work, particularly those for optically allowed transitions, should be more accurate than the corresponding data given by Zhang and Sampson [H.L. Zhang, D.H. Sampson, At. Data Nucl. Data Tables 63 (1996) 275] and are presented here to replace those earlier results.

Relativistic distorted-wave collision strengths for the 49 [formula omitted] optically allowed transitions with [formula omitted] in the 67 N-like ions with [formula omitted

Relativistic distorted-wave collision strengths have been calculated for the 49 Δn=0 optically allowed transitions with n=2 in the 67 N-like ions with nuclear charge number Z in the range 26≤Z≤92. The calculations were made for the four final, or scattered, electron energies E′=0.20, 0.42, 0.80, and 1.40, where E′ is in units of Zeff2 Ry with Zeff=Z−5. In the present calculations, an improved “top-up” method, which employs relativistic plane waves, was used to obtain the high partial-wave contribution for each transition, in contrast to the partial-relativistic Coulomb–Bethe approximation used in the previous work by Zhang and Sampson [H.L. Zhang and D.H. Sampson, At. Data Nucl. Data Tables 72 (1999) 153]. In that earlier work, collision strengths were also provided for N-like ions, but for a more comprehensive data set consisting of all possible 105 Δn=0 transitions, six scattered energies and the 81 ions with Z in the range 12≤Z≤92. The collision strengths covered in the present work should be more accurate than the corresponding data given by Zhang and Sampson [H.L. Zhang and D.H. Sampson, At. Data Nucl. Data Tables 72 (1999) 153] and are presented here to replace those earlier results.

Relativistic distorted-wave collision strengths for the 49 [formula omitted] optically allowed transitions with [formula omitted] in the 67 B-like ions with [formula omitted

Relativistic distorted-wave collision strengths have been calculated for the 49 Δn=0 optically allowed transitions with n=2 in the 67 B-like ions with nuclear charge number Z in the range 26≤Z≤92. The calculations were made for the four final, or scattered, electron energies E′=0.20, 0.42, 0.80, and 1.40, where E′ is in units of Zeff2 Ry with Zeff=Z−3.33. In the present calculations, an improved “top-up” method, which employs relativistic plane waves, was used to obtain the high partial-wave contribution for each transition, in contrast to the partial-relativistic Coulomb–Bethe approximation used in previous work by Zhang and Sampson [H.L. Zhang and D.H. Sampson, At. Data Nucl. Data Tables 56 (1994) 41]. In that earlier work, collision strengths were also provided for B-like ions, but for a more comprehensive data set consisting of all 105 Δn=0 transitions, six scattered energies and the 85 ions with Z in the range 8≤Z≤92. The collision strengths covered in the present work should be more accurate than the corresponding data given by Zhang and Sampson [H.L. Zhang and D.H. Sampson, At. Data Nucl. Data Tables 56 (1994) 41] and are presented here to replace those earlier results.

Relativistic distorted-wave collision strengths for the [formula omitted] optically allowed transitions with [formula omitted] in the 67 Be-like ions with [formula omitted

Relativistic distorted-wave collision strengths have been calculated for the 16 Δn=0 optically allowed transitions with n=2 in the 67 Be-like ions with nuclear charge number Z in the range 26≤Z≤92. The calculations were made for the four final, or scattered, electron energies E′=0.20, 0.42, 0.80, and 1.40, where E′ is in units of Zeff2 Ry with Zeff=Z−2.5. In the present calculation, an improved “top-up” method, which employs relativistic plane waves, was used to obtain the high partial-wave contribution for each transition, in contrast to the partial-relativistic Coulomb–Bethe approximation used in previous work by Zhang and Sampson [H.L. Zhang and D.H. Sampson, At. Data Nucl. Data Tables 52 (1992) 143]. In that earlier work, collision strengths were also provided for Be-like ions, but for a more comprehensive data set consisting of all 45 Δn=0 transitions, six scattered energies, and the 85 ions with Z in the range 8≤Z≤92. The collision strengths covered in the present work should be more accurate than the corresponding data given by Zhang and Sampson [H.L. Zhang and D.H. Sampson, At. Data Nucl. Data Tables 52 (1992) 143] and are presented here to replace those earlier results.

RELATIVISTIC DISTORTED-WAVE COLLISION STRENGTHS AND OSCILLATOR STRENGTHS FOR THE 45Δ n=0 TRANSITIONS WITH n=2 IN THE 79 O-LIKE IONS WITH 14≤ Z≤92

Relativistic distorted-wave collision strengths have been calculated for the 45 Δ n=0 transitions with n=2 in the 79 O-like ions with nuclear charge number Z in the range 14≤ Z≤92. The calculations were made for the six final, or scattered, electron energies E′=0.03, 0.08, 0.20, 0.42, 0.80, and 1.40, where E′ is in units of Z 2 eff Ry with Z eff= Z−5.83. In addition, the transition energies and electric dipole oscillator strengths are given. To our knowledge the present work is the first comprehensive publication of the results of fully relativistic calculations of the collision strengths for excitation of highly charged O-like ions.

RELATIVISTIC DISTORTED-WAVE COLLISION STRENGTHS AND OSCILLATOR STRENGTHS FOR THE 105 Δn = 0 TRANSITIONS WITH n = 2 IN THE 81 N-LIKE IONS WITH 12 ≤ Z ≤ 92

Relativistic distorted-wave collision strengths have been calculated for the 105 Δn = 0 transitions with n = 2 in the 81 N-like ions with nuclear charge number Z in the range 12 ≤ Z ≤ 92. The calculations were made for the six final, or scattered, electron energies E′ = 0.03, 0.08, 0.20, 0.42, 0.80, and 1.40, where E′ is in units of Z2eff Ry with Zeff = Z − 5. In addition, the transition energies and electric dipole oscillator strengths are given. To our knowledge the present work is the first comprehensive publication of the results of fully relativistic calculations of the collision strengths for excitation of highly charged N-like ions.

Atomic data from the IRON Project

Collision strengths for electron induced tran- sitions in Li-like Fe xxiv are calculated using a Breit- Pauli R-matrix technique. The target has 15 ne struc- ture states corresponding to n 4. Autoionizing reso- nances are found to aect 18 of the 39 collision strengths, namely those for transitions 2lj!n 0 l 0 j 0 where n 0 =2 ; 3 : The present calculation is carried out only for electrons incident on the ground state with energies not exceeding 265 Ry. Beyond this we use the relativistic distorted wave collision strengths of Zhang et al. in order to complete our results. Thermally averaged collision strengths are com- puted and tabulated as functions of logT for transitions out of the 2s1=2 ,2 p 1 = 2 and 2p3=2 states. The temperature range considered is 6:2 log T 8:0, Fe xxiv having its maximum coronal abundance when logT =7 :2.

RELATIVISTIC DISTORTED-WAVE COLLISION STRENGTHS AND OSCILLATOR STRENGTHS FOR ALL POSSIBLEn= 2–n= 3 TRANSITIONS IN C-LIKE IONS

Relativistic distorted-wave collision strengths have been calculated for the over 4000n= 2–n= 3 transitions in the 46 C-like ions with nuclear charge numberZin the range 9 ≤Z≤ 54, but in the interest of brevity the results are given here for only the three valuesZ= 12, 26, and 54. The calculations were made for the six final, or scattered, electron energiesE′ = 0.008, 0.04, 0.12, 0.28, 0.60, and 1.20, whereE′ is in units ofZeff2rydbergs withZeff= Z− 4.17. In addition, the transition energies and electric dipole oscillator strengths are given. To our knowledge the present work is the first publication of the results of fully relativistic calculations of the collision strengths for excitation of highly charged C-like ions to then= 3 levels.

Relativistic Distorted-Wave Collision Strengths and Oscillator Strengths for the Δ n= 0 Transitions with n= 2 in C-Like Ions with 9 ≤ Z≤ 54

Relativistic distorted-wave collision strengths have been calculated for the Δ n= 0 transitions with n= 2 in C-like ions with nuclear charge number Zin the range 9 ≤ Z≤ 54. The calculations were made for the six final, or scattered, electron energies E′ = 0.03, 0.08, 0.20, 0.42, 0.80, and 1.40, where E′ is in units of Z 2 effRydbergs with Z eff = Z− 4.17. In addition, the transition energies and electric dipole oscillator strengths are given. To our knowledge the present work is the first publication of the results of fully relativistic calculations of the collision strengths for excitation of highly charged C-like ions.

Relativistic collision strengths for optically allowed Delta n=0 transitions between magnetic sublevels of highly charged ions.

Procedures are given for calculating relativistic distorted-wave collision strengths for producing optically allowed \ensuremath{\Delta}n=0 transitions between magnetic sublevels of highly charged ions by impact with directional electrons. For such transitions, which tend to have very small transition energies, difficulties arise because the contribution from extremely large angular momenta of the free electron is important. Illustrative numerical results are given for He-like ions, which have been of interest for electron-beam ion-trap experiments [Wargelin et al., Phys. Rev. Lett. 71, 2196 (1993)].

Relativistic Distorted-Wave Collision Strengths and Oscillator Strengths for All Possible n = 2 - n = 3 Transitions in B-Like Ions

Relativistic distorted-wave collision strengths have been calculated for the nearly 1650 n = 2 - n = 3 transitions in the 85 B-like ions with nuclear charge number Z in the range 8 ≤ Z ≤ 92, but in the interest of brevity the results are given here for only the four values Z = 14, 26, 42, and 64. The calculations were made for the six final, or scattered, electron energies E′ = 0.008, 0.04, 0.12, 0.28, 0.60, and 1.20, where E′ is in units of Z2eff rydbergs with Zeff = Z − 3.33. In addition, the transition energies and electric dipole oscillator strengths are given. To our knowledge the present work is the first publication of the results of fully relativistic calculations of the collision strengths for excitation of highly charged B-like ions to the n = 3 levels.

Relativistic Distorted-Wave Collision Strengths and Oscillator Strengths for the 105 Δ n = 0 Transitions with n = 2 in the 85 B-Like Ions with 8 ≤ Z ≤ 92

Relativistic distorted-wave collision strengths have been calculated for the 105 Δ n = 0 transitions with n = 2 in the 85 B-like ions with nuclear charge number Z in the range 8 ≤ Z ≤ 92. The calculations were made for the six final, or scattered, electron energies E′ = 0.03, 0.08, 0.20, 0.42, 0.80, and 1.40, where E′ is in units Z 2 eff rydbergs with Z eff = Z − 3.33. In addition, the transition energies and electric dipole oscillator strengths are given. To our knowledge the present work is the first comprehensive publication of the results of fully relativistic calculations of the collision strengths for excitation of highly charged B-like ions.