Collisional excitation rates of complex atomic ions by electron impact

Abstract

For many applications, a large number of rate coefficients for electron impact excitation are needed. These rate coefficients may be obtained by integration of the collision strength. Fits to collision strengths are presented as a function of both the nuclear change Z and X, the impact electron energy in threshold units. The collision strength fit form is readily integrated over a Maxwellian distribution and has fitted extensive distorted wave data to nearly 5% from singly ionized stages to molybdenum for 19 spin-allowed transitions of the isoelectric sequences of hydrogen, helium, lithium, beryllium, boron, sodium, and magnesium. The excitation energies have been fitted as a function of Z to better than 1%.