K. M. Aggarwal

Electron collision cross sections at low energies for all transitions between the n=1, 2, 3, 4 and 5 levels of atomic hydrogen

Collision strengths for all transitions among states up to the n=5 level are reported in the energy range below 1.96 Ryd. The R-matrix and no-exchange programs have been used for partial waves with L 9 respectively. The results are analysed in detail highlighting the resonance structure. They are also compared with other results. The effective collision strengths obtained after averaging the collision strengths over a Maxwellian distribution of electron velocities are listed at temperatures below 50000 K. Though the results require an improvement especially in the intermediate energy region, nevertheless they are probably the best available for most of the transitions.

Oscillator Strengths for Transitions in C-like Ions between F IV and Ar XIII

Energy levels and oscillator strengths (transition probabilities) have been calculated for the fine-structure transitions among the levels of the (1s2) 2s22p2, 2s2p3, 2p4, 2s22p3s, 2s22p3p, and 2s22p3d configurations of C-like F IV, Na VI, Al VIII, P X, Cl XII, and Ar XIII using the CIV3 program. The extensive configuration interaction and relativistic effects have been included while generating the wavefunctions. Calculated values of energy levels generally agree within 5% with the experimentally compiled results, and the length and velocity forms of oscillator strengths agree within 20% for a majority of allowed transitions.

Excitation rate coefficients for transitions among the n = 1, 2, and 3 levels of He+

Excitation rate coefficients for transitions among the n = 1, 2, and 3 levels of He + are reported in the temperature range of 5 × 10 3 -5 × 10 5 K. These are based on the best available R-matrix collision strengths of Aggarwal et al. (1991, J. Phys., B., 24) in the threshold energy region including resonances and of the pseudostate close coupling calculations of Unnikrishnan et al. (1991, Phys. Rev. A, A43) at energies above thresholds. Comparisons with the earlier available effective collision strengths are made and differences are discussed

Energy levels, radiative rates and electron impact excitation rates for transitions in He-like N VI, F VIII and Na X

In this paper, we report calculations for energy levels, radiative rates and electron impact excitation rates for transitions in He-like N VI, F VIII and Na X. The general-purpose relativistic atomic structure package (grasp) is adopted for calculating energy levels and radiative rates, and for determining the collision strengths and subsequently the excitation rates, the Dirac atomic R-matrix code (darc) and the flexible atomic code (fac) are used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 49 levels of N VI, F VIII and Na X. Collision strengths have been averaged over a Maxwellian velocity distribution and the effective collision strengths so obtained are reported over a wide temperature range below 107 K. Additionally, lifetimes are also reported for all calculated levels of the above three ions.

Relativistic allowed and forbidden transition probabilities for fluorine-like Fe XVIII

Energy levels and the corresponding transition probabilities for allowed and forbidden transitions among the levels of the ground configuration and first 23 excited configurations of fluorine-like Fe  have been calculated using the mul- ticonfigurational Dirac-Fock  code. A total of 379 lowest bound levels of Fe  is presented, and the energy levels are identified in spectroscopic notations. Transition probabilities, oscillator strengths and line strengths for electric dipole (E1), electric quadrupole (E2) and magnetic dipole (M1) transitions among these 379 levels are also presented. The calculated energy levels and transition probabilities are compared with experimental data.

Energy levels, radiative rates and electron impact excitation rates for transitions in Fe xiv

Energies and lifetimes are reported for the lowest 136 levels of Fe XIV, belonging to the (1s

Energy levels, radiative rates and electron impact excitation rates for transitions in He-like Mg XI, Al XII, P XIV and S XV

^2

Energy levels, radiative rates and electron impact excitation rates for transitions in Si XII, Si XIII and Si XIV

2s

Electron impact excitation of Fe XIII

^2

Radiative rates for transitions in Fe XVII

2p