Atomic data from the IRON Project - XXX. Collision data for the (2)P(o)1/2-(2)P(o)3/2 fine-structure lines of P III, S IV and Cl V

This is the third paper in a series giving collision rates for electron exc itation of the P-2(1/2)o -P- 2(3/2)o 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 us ing a method which does not incorporate resonance effects. For S IV, previo us close-coupling calculations do exist but we show that our more elaborate calculation changes the rate coefficients by about 50% at lower temperatur es.