The functional fit to the rate coefficients for collisional de-excitation takes the
where , and a value of was adopted in all the fits. This last parameter prevents divergence of the rate coefficients as .
Files are included for de-excitation of para-H2 and ortho-H2 (merged into a single file) by H, and HD by H; these files are called, respectively, h2h_decal1_fit.txt , and hhd_decal1_fit.txt In each file, the first line specifies the total number of transitions. Subsequent lines contain, in 5 successive columns: an index identifying the initial (upper) state; an index identifying the final (lower) state; value of a; value of b; value of c. The ordering (and identification) of the levels is according to energy, commencing with the lowest J=0, v=0 state of H2 or HD. The energetic ordering of the pairs of values of (J,v) is to be found in the files: h2_levels_in.txt and hd_levels_in.txt