Excitation rate coefficients from the ground state of atomic hydrogen to the n = 2 and n = 3 levels

Electron excitation rate coefficients have been calculated for excitation of the ground state of atomic hydrogen to the n = 2 and 3 levels over a wide temperature range. These are based upon the best assessed collision cross-sections, both experimental and theoretical, available in the literature. A comparison of the present results with those of the earlier calculation shows a difference of as much as a factor of 9 at some temperatures. Analytic expressions are given for the effective collision strengths so that these can be easily used to get the rate coefficients at any desired temperature. (author)