2003ApJ...582..550T

The Breit-Pauli R-matrix with pseudostates approach has been used to calculate electron collisional excitation strengths for transitions between the 24 lowest fine-structure levels belonging to 14 LS terms (ns²S, np²P⁰ [n=2-5], nd²D [n=3-5], nf²F⁰ [n=4, 5], and 5g²G) of O VI. The effects of coupling to the highly excited bound and continuum target states have been simulated by using a set of pseudostates in the close-coupling expansion. Our 43 state Breit-Pauli calculation includes 24 physical and 19 pseudolevels in the R-matrix expansion. Rydberg series of resonances converging to the excited level thresholds are explicitly included in the calculation. The effective collision strengths are obtained from the total collision strengths by integrating over a Maxwellian velocity distribution of electron energies. These are listed over a wide temperature range from 10³ to 6x10⁶ K.