Rate Coefficients for Electron Excitation of the First Resonance Transition in h, Li, Na, Ca, Ca', and Ba' Calculated from Experimental Data

By fitting cubic splines augmented with special functional forms for low and high energies to cross-section data determined experimentally at discrete values of the electron energy, we obtain an interpolation that can be visually inspected and adjusted to prevent the appearance of spurious features. The familiar integral expressing the rate coefficient in terms of the cross-sections can then be evaluated with no further approximation. This procedure is applied here to cross-section data for the first resonance transition of H, Li, Na, Ca, Ca +, and Ba +. The resulting collisional de-excitation rate coefficient, from which the excitation-rate coefficient can be determined by the detailed balance relation, is tabulated in each case for electron temperatures in the interval from 1O to 1O K and is expressed in terms of a Chebyshev expansion valid for this range of temperature. Subject heading: transition probabilities