Effective collision strengths for fine-structure forbidden transitions among the 2s(2)2p(3) levels of S x

Effective collision strengths for electron-impact excitation of the N-like ion Sr are calculated in the close-coupling approximation using the multich annel R-matrix method. Specific attention is given to the 10 astrophysicall y important fine-structure forbidden transitions among the S-4(o), D-2(o) a nd (2)p(o) levels in the 2s(2)2p(3) ground configuration. The total (e(-) ion) wavefunction is expanded in terms of the 11 lowest LS eigenstates of S x, and each eigenstate is represented by extensive configuration-interact ion wavefunctions. The collision strengths obtained are thermally averaged over a Maxwellian distribution of velocities, for all 10 fine-structure tra nsitions, over the range of electron temperatures logT(K) = 4.6-6.7 (the ra nge appropriate for astrophysical applications). The present effective coll ision strengths are the only results currently available for these fine-str ucture transition rates.