Paper XXX

Collision data for the $^2$P $^\circ_{1/2}-^2$P$^\circ_{3/2}$ fine-structure lines of P III, S IV and Cl V.

H.E. Saraph and P.J. Storey

Astronomy & Astrophysics Supplement Series, 1999, Vol.134, pp.369-375

This is the third paper in a series giving collision rates of the $^2$P $^\circ_{1/2}-^2$P$^\circ_{3/2}$ ground state fine-structure transition in aluminium-like ions. In this paper we give data for the transitions in P III (17.9 $\mu$m), S IV (10.5 $\mu$m) and Cl V (6.71 $\mu$m). For the P and Cl ions the only existing results are nearly 30 years old and were obtained using a method which does not incorporate resonance effects. For S IV, previous close-coupling calculations do exist but we show that our more elaborate calculation changes the rate coefficients by about 50% at lower temperatures.