Fully relativistic distorted wave calculations of electron impact excitation of gallium atom: Cross sections relevant for plasma kinetic modeling

Electron impact excitation cross sections of neutral Ga are calculated using the relativistic distorted wave approximation with the aid of multiconfigurational Dirac-Fock wavefunctions. The cross sections are calculated from the fine structure resolved levels of the 4s24p manifold, i.e., from the ground (2P1/2) and the first excited state (2P3/2), to the fine structure resolved levels of the manifolds 4s24[p, d, f], 4s4p2(4P1/2, 4P3/2, and 4P5/2), 4s25[s, p, d, f], 4s26[s, p, d, f], 4s27[s, p, d, f], and 4s28[s, p, d, f] for incident electron energies ranging from threshold to 500 eV. Where available, a comparison of the calculated oscillator strengths, transition probabilities, and cross sections with the previously reported results has been performed. The cross sections for the excitation from 4s24p(2P1/2) to 4s24f, 4s4p2(4P1/2, 4P3/2, and 4P5/2), 4s25f, 4s26f, 4s27[d, f], and 4s28[s, p, d, f] and all the excitation cross sections from 4s24p(2P3/2) are calculated and reported for the first time for a wide range of electron energies. Furthermore, the rate coefficients are also calculated using the present cross sections for an electron temperature varying from 0.5 to 5 eV. An analytic fitting of the calculated rate coefficients is provided to facilitate their inclusion in various plasma kinetic models.