Effective collision strengths for electron impact excitation of C1III

Effective collision strengths for electron-impact excitation of the phospho rus-like ion Cl III are presented for all fine-structure transitions among the levels arising from the lowest 23 LS states. The collisional cross sect ions are computed in the multichannel close-coupling R-matrix approximation , where sophisticated configuration-interaction wave functions are used to represent the target states. The 23 LS states are formed from the basis con figurations 3s(2)3p(3). 3s3p(4). 3s(2)3p(2)3d, and 3s(2)3p(2)4s, and corres pond to 49 fine-structure levels, leading to a total possible 1176 fine-str ucture transitions. The effective collision strengths. obtained by averagin g the electron collision strengths over a Maxwellian distribution of electr on velocities. are tabulated in this paper for all 1176 transitions and for electron temperatures in the ranges T(K) = 7500-25.000 and log T(K) = 4.4- 5.3. The former range encompasses the temperatures of particular importance for application to gaseous nebulae. while the latter range is more applica ble to the study of solar and laboratory-type plasmas. (C) 2001 Academic Pr ess.